Input: mark {corgi,spitz,tosa}kbd drivers deprecated

Provided that now keyboards on these devices are fully supported by
generic GPIO based matrix keypad driver, mark these hardcoded and
difficult to maintain drivers as deprecated.

Signed-off-by: Eric Miao <eric.y.miao@gmail.com>
Acked-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>