ARM: mach-shmobile: ag5evm: scan keyboard support

This consists of platform device resources/data for the board, and
simple clvdev entry for MSTP bit for keysc module.

This support only 49 of 80 key-switches on the board.

Signed-off-by: Takashi YOSHII <takashi.yoshii.zj@renesas.com>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>