Input: kbtab - do not advertise unsupported events

The device does not emit EV_MSC/MSC_SERIAL nor EV_KEY/BTN_MIDDLE events
so it should not mark them as supported in capabilities bitmaps. This
still leaves BTN_TOOL_PEN and BTN_TOUCH events being processed in a funky
manner.

Signed-off-by: Dmitry Torokhov <dtor@mail.ru>