IBMPC-USB: XT/AT Auto-Switcing - Copam K-430

[tmk]

Copam K-430 is an AT/XT Auto-Switching keyboard with "AA with parity error" method. https://geekhack.org/index.php?topic=111510.msg3086764#msg3086764

TMK IBMPC converter recognizes it as a XT keyboard because the converter doesn't detect and recover parity error.

• Deteciting parity error to send command(FE or FF) is need to communicate with the keyboard on AT protocol.
• In general AT protocol is preferable to XT for keyboard functionality.
• It would be useful for debug purpose if user can select protocol by some way or other.

"AA with parity error" method: https://github.com/tmk/tmk_keyboard/wiki/IBM-PC-Keyboard-Converter#aa-with-parity-error

[tmk]

Added support at 16ff313820ce576e5f933e6bb133fc1d771ecda4