Input: atakbd - fix Atari CapsLock behaviour

The CapsLock key on Atari keyboards is not a toggle, it does send the
normal make and break scancodes.

Drop the CapsLock toggle handling code, which did cause the CapsLock
key to merely act as a Shift key.

Tested-by: Michael Schmitz <schmitzmic@gmail.com>
Signed-off-by: Michael Schmitz <schmitzmic@gmail.com>
Signed-off-by: Andreas Schwab <schwab@linux-m68k.org>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>