ARM: rockchip: enable PMU_GPIOINT_WAKEUP_EN when entering shallow suspend

PMU_GPIOINT_WAKEUP_EN seems needed when entering the shallow suspend
(with logic staying on) but does not seem to be needed for the deep
suspend for unknown reasons.
Testing revealed that this setting really is necessary to reliably
resume the veyron devices from suspend.

Reported-by: Chris Zhong <zyw@rock-chips.com>
Signed-off-by: Heiko Stuebner <heiko@sntech.de>
Reviewed-by: Chris Zhong <zyw@rock-chips.com>
Tested-by: Chris Zhong <zyw@rock-chips.com>
Reviewed-by: Douglas Anderson <dianders@chromium.org>