Input: tegra-kbc - fix wakeup from suspend

For wakeup to be reliable, kbc needs to be in interrupt mode before suspend.
Created common routine to control the FIFO interrupt.
Added synchronization to ensure orderly suspend.

Signed-off-by: Rakesh Iyer <riyer@nvidia.com>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>