ARM: shmobile: bockw: add SDHI0 support

This patch is directly accessing to PUPR4 register which can
control SDHI0 CD/WP pin pull-up setting.
It should be replaced in the future.

Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>