Input: adp5589-keys - use BIT()

Let's use BIT() macro instead of explicitly shifting '1'.

Acked-by: Alexandru Ardelean <Alexandru.ardelean@analog.com>
Link: https://lore.kernel.org/r/20201119072440.GA116840@dtor-ws


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