piolib: add Pico SDK 2 PIO API #159

piolib.h is missing the new functions and updates/fixes from Pico C/C++ SDK 2, like (probably not all make sense [but might be convenient for portable code], and probably some are missing, but at least the ones used by pioasm-generated code using pico-sdk-tools ≥ v2.0.0 should be available):

sm_config_set_out_pin_base
sm_config_set_out_pin_count
sm_config_set_set_pin_base
sm_config_set_set_pin_count
sm_config_set_in_pin_base
sm_config_set_in_pin_count
sm_config_set_sideset_pin_base
sm_config_set_clkdiv_int_frac8
pio_enable_sm_mask_in_sync
pio_sm_get_pc
pio_sm_is_exec_stalled
pio_sm_set_wrap
pio_sm_set_out_pins
pio_sm_set_set_pins
pio_sm_set_in_pins
pio_sm_set_sideset_pins
pio_sm_set_jmp_pin
pio_sm_set_clkdiv_int_frac8
pio_sm_set_pins64
pio_sm_set_pins_with_mask64
pio_claim_free_sm_and_add_program
pio_claim_free_sm_and_add_program_for_gpio_range
pio_remove_program_and_unclaim_sm
pio_get_irq_num
pio_get_tx_fifo_not_full_interrupt_source
pio_get_rx_fifo_not_empty_interrupt_source
pio_set_gpio_base
pio_get_gpio_base
pio_get_funcsel
pio_get_instance
pio_get_dreq
pio_encode_sideset_opt
pio_sm_set_consecutive_pins

Update: some have been added in #226