sh: Add support pin function control using GPIO

Renesas SH and R-Mobile set up device using PFC.
This provide the framework. Most codes were brought from linux kernel.

Signed-off-by: Nobuhiro Iwamatsu <nobuhiro.iwamatsu.yj@renesas.com>
Signed-off-by: Nobuhiro Iwamatsu <iwamatsu@nigauri.org>