Input: ep93xx_keypad - use BIT() and GENMASK() macros

Also drop parenthesis around macros that do not use expressions as they are
not needed.

Acked-by: Alexander Sverdlin <alexander.sverdlin@gmail.com>
Link: https://lore.kernel.org/r/20211012013735.3523140-2-dmitry.torokhov@gmail.com


Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>