Input: add support for Nomadik SKE keypad controller

Add support for the keypad controller in the Scroll Key Encoder (SKE)
module on the Nomadik family and the DB8500 SoC.

Acked-by: Linus Walleij <linus.walleij@stericsson.com>
Signed-off-by: Sundar Iyer <sundar.iyer@stericsson.com>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>