This initializes GPIO, without using PFC framework in
board_early_init_f function. It is because it cannot initialize
normally when PFC is used.

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