Input: samsung-keypad - use BIT() and GENMASK() where appropriate

Instead of using (1 << <shift>) construct use BIT() helper. Convert (1
<< <shift>) - 1 to GENMASK().

Link: https://lore.kernel.org/r/20240819045813.2154642-9-dmitry.torokhov@gmail.com


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