boards/rp2040: add USB fastboot support for waveshare boards

[JianyuWang0623]

Summary

Adds USB fastboot support for the waveshare RP2040 boards and fixes a
real RP2040 usbdev driver bug found in the process (Stage 2 of the
"RP2040 waveshare series optimization" work, following the already
merged reboot-bootloader change in #20059).

• boards/arm/rp2040/common/src/rp2040_composite.c: add a third
  composite slot for CONFIG_USBADB (the generic ADB driver, which
  with CONFIG_USBFASTBOOT becomes the "fastboot" personality)
  alongside the existing MSC/CDC-ACM slots.
• New fastboot_usb defconfig for waveshare-rp2040-zero and
  waveshare-rp2040-lcd-1.28: boots directly into fastbootd
  (CONFIG_INIT_ENTRYPOINT="fastbootd_main", no nsh) and brings up a
  CDC/ACM (console) + USB fastboot composite device via
  CONFIG_SYSTEM_FASTBOOTD_USB_BOARDCTL, so the CDC/ACM sub-interface
  still provides console/log visibility without a wired UART, while
  the fastboot vendor interface is what fastboot devices/getvar
  talk to.
• arch/arm/src/rp2040/rp2040_usbdev.c: fix a bug in
  rp2040_allocep() that this new fastboot config exposed. It indexes
  the endpoint's DPSRAM buffer/control registers via
  RP2040_DPINDEX(eplog)/RP2040_EPINDEX(eplog), both of which take
  the transfer direction from the direction bit of eplog itself
  instead of trusting the explicit in argument also passed to this
  function. This is harmless for callers that always encode the
  direction bit into eplog (e.g. CDC/ACM's
  CDCACM_MKEPBULKIN()/MKEPINTIN(), which OR in USB_DIR_IN), but
  drivers/usbdev/usbdev_fs.c (the generic ADB/fastboot class driver)
  calls DEV_ALLOCEP() with a bare endpoint number in eplog (no
  direction bit) and passes direction only via in - matching this
  function's own "direction bit ignored" contract for eplog. For
  such a bare-number IN endpoint, USB_ISEPOUT(eplog) always
  evaluates true, so RP2040_DPINDEX(eplog) silently pointed the
  endpoint's buffer/control registers at its OUT slot instead of its
  IN slot, leaving the real IN slot unconfigured; the SIE then
  responds to every IN token on that endpoint with a STALL. The fix
  normalizes eplog to agree with in once, up front, so both
  macros keep their original single-argument form.

Impact

• RP2040 only.
• The rp2040_allocep() fix affects every RP2040 board, but only
  changes behavior for callers that pass a bare (no direction bit)
  eplog, which today is exactly the generic ADB/fastboot driver;
  existing CDC/ACM/MSC/composite configs already encode the direction
  bit and are unaffected (verified: no behavior change observed on
  the existing usbnsh/composite configs used in prior testing).

Testing

Host: Ubuntu (x86_64), arm-none-eabi-gcc, built with
make PICO_SDK_PATH=<pico-sdk> (required for the boot2 stage to be
included in the generated .uf2).

Board: waveshare-rp2040-lcd-1.28 (physically connected over USB via
picotool/BOOTSEL for flashing). waveshare-rp2040-zero's
fastboot_usb defconfig was build-tested only (no second physical
board available in this environment).

Before the rp2040_usbdev.c fix, the fastboot USB interface enumerated
correctly but every response from device to host hard-STALLed.
Captured with usbmon on a getvar:product request:

S Bo:1:050:7 -115 14 = 67657476 61723a70 726f6475 6374   (OUT "getvar:product", host->device, succeeds)
C Bo:1:050:7 0 14 >
S Bi:1:050:6 -115 64 <                                    (IN, device->host, host requests the reply)
C Bi:1:050:6 -32 0                                        (completes with errno -32 = EPIPE, i.e. a real STALL)

After the fix, on the same board/defconfig:

$ lsusb -v -d 03eb:2023 | grep -E "bInterfaceNumber|bInterfaceClass"
      bInterfaceNumber        0
      bInterfaceClass         2 Communications
      bInterfaceNumber        1
      bInterfaceClass        10 CDC Data
      bInterfaceNumber        2
      bInterfaceClass       255 Vendor Specific Class

$ fastboot devices
0101	fastboot

$ fastboot getvar product
product: NuttX
Finished. Total time: 0.001s

$ fastboot reboot bootloader
Rebooting into bootloader                          OKAY [  0.000s]

dmesg shows clean enumeration with no can't set config errors and
all three interfaces bound:

usb 1-5.4: New USB device found, idVendor=03eb, idProduct=2023, bcdDevice=10.10
usb 1-5.4: Product: NuttX Fastboot Composite
usb 1-5.4: Manufacturer: NuttX
cdc_acm 1-5.4:1.0: ttyACM5: USB ACM device

tools/nxstyle and tools/checkpatch.sh are clean for both commits'
actual changed lines (spot-checked directly; checkpatch.sh -g HEAD
reports All checks pass; some pre-existing, unrelated nxstyle
violations in rp2040_usbdev.c predate this series - confirmed via
git blame to point at the original 2021 driver commit b860e3c4ad35

• and are not touched by either commit here).

[github-actions]

MemBrowse Memory Report

No memory changes detected for:

• arduino-mega2560
• esp32-devkitc
• hifive1-revb
• mirtoo
• qemu-armv8a
• qemu-intel64
• rx65n-rsk2mb
• s698pm-dkit
• stm32-nucleo-f103rb

[acassis]

@JianyuWang0623 please add fastboot_usb to the board Documentation to list it and explain how to use

[JianyuWang0623]

@JianyuWang0623 please add fastboot_usb to the board Documentation to list it and explain how to use

@acassis done, "Documentation/rp2040: document fastboot_usb config for waveshare boards"