pinctrl: mediatek: Implement wake handler and suspend resume

This patch implement irq_set_wake to get who is wakeup source and
setup on suspend resume.

Signed-off-by: Maoguang Meng <maoguang.meng@mediatek.com>
Reviewed-by: Daniel Kurtz <djkurtz@chromium.org>
Acked-by: Yingjoe Chen <yingjoe.chen@mediatek.com>
Acked-by: Hongzhou Yang <hongzhou.yang@mediatek.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>