Input: add driver for Maxim MAX7359 key switch controller

The Maxim MAX7359 is a I2C interfaced key switch controller which
provides microprocessors with management of up to 64 key switches.
This patch adds support for the MAX7359 key switch controller.

Signed-off-by: Kim Kyuwon <q1.kim@samsung.com>
Reviewed-by: Trilok Soni <soni.trilok@gmail.com>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>