ARM: mach-shmobile: sh73a0: add MMC data pin pull-up

This patch adds MMC data pin pull-up option for pfc-sh73a0.c,
and select it on ag5evm board.
The MMC read/write will be error without this patch.

Cc: Takashi YOSHII <takashi.yoshii.zj@renesas.com>
Tested-by: Simon Horman <horms@verge.net.au>
Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>