Input: samsung-keypad - Add samsung keypad driver

This patch adds support for keypad driver running on Samsung cpus. This
driver is tested on GONI and Aquila board using S5PC110 cpu.

[ch.naveen@samsung.com: tested on SMDK6410, SMDKC100, and SMDKV210]
Signed-off-by: Joonyoung Shim <jy0922.shim@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Tested-by: Naveen Krishna Ch <ch.naveen@samsung.com>
Acked-by: Kukjin Kim <kgene.kim@samsung.com>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>