Fix strange media key for PS/2 keyboard in a driver

[Werner Sembach <wse@xxxxxxxxxxxxxxxxxxx>]

Hi,

TongFang/Uniwill Notebook barebones have their internal keyboard connected via 
PS/2 and pressing the touchpad toggle media key sends the 3 key combo 
KEY_LEFTMETA + KEY_LEFTCTRL + KEY_ZENKAKUHANKAKU.

If it were a HID keyboard I could use a HID-BPF program to remap this 3 key 
combo to a singular press of F21 which seems to be the default for touchpad 
toggle and now I wonder if something similar is possible for PS/2 keyboards?

Kind regards,

Werner