*_POLARITY attributes are not used to invert incoming signals at ports

[Flojo101]

As reported in FEntwumS/FEntwumS.NetlistViewer#57, input ports where the incoming signal is expected to be inverted are not marked as such. This is due to the backend not using the *_POLARITY attributes. The example provided in the original issue produces the following two ADFFs:

"$procdff$13": {
          "hide_name": 1,
          "type": "$adff",
          "parameters": {
            "ARST_POLARITY": 1,
            "ARST_VALUE": 0,
            "CLK_POLARITY": 0,
            "WIDTH": 1
          },
          "attributes": {
            "src": "C:\\[...]\\cclk2enph.v:17.5-19.31"
          },
          "port_directions": {
            "ARST": "input",
            "CLK": "input",
            "D": "input",
            "Q": "output"
          },
          "connections": {
            "ARST": [ 3 ],
            "CLK": [ 2 ],
            "D": [ 12 ],
            "Q": [ 11 ]
          }
        },
        "$procdff$16": {
          "hide_name": 1,
          "type": "$adff",
          "parameters": {
            "ARST_POLARITY": 1,
            "ARST_VALUE": 0,
            "CLK_POLARITY": 1,
            "WIDTH": 1
          },
          "attributes": {
            "src": "C:\\[...]\\cclk2enph.v:11.5-13.34"
          },
          "port_directions": {
            "ARST": "input",
            "CLK": "input",
            "D": "input",
            "Q": "output"
          },
          "connections": {
            "ARST": [ 3 ],
            "CLK": [ 2 ],
            "D": [ 13 ],
            "Q": [ 12 ]
          }
        }

The first ADFF should have inverted the clock signal at the input port, as indicated by the CLK_POLARITY parameter.