Input: add new driver for ARM CLPS711X keypad

This patch adds a new driver for keypad for Cirrus Logic CLPS711X CPUs.
Target CPU contain keyboard interface which can scan 8 column lines,
so we can read row GPIOs to read status and determine asserted state.

Signed-off-by: Alexander Shiyan <shc_work@mail.ru>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

diff --cc Documentation/devicetree/bindings/input/clps711x-keypad.txt
Simple merge

diff --cc drivers/input/keyboard/Kconfig
Simple merge

diff --cc drivers/input/keyboard/Makefile
Simple merge

diff --cc drivers/input/keyboard/clps711x-keypad.c
Simple merge