ARM: RX1950: configure GPG13-15 as input before suspend

According to datasheet GPG13-15 must be configured as input in NAND
boot mode, otherwise device will not be able to wake up

Signed-off-by: Vasily Khoruzhick <anarsoul@gmail.com>
Signed-off-by: Ben Dooks <ben-linux@fluff.org>