ARM: dts: rockchip: vdd_gpu off in suspend for rk3288-veyron

At some point long long ago the downstream GPU driver would crash if
we turned the GPU off during suspend.  For some context you can see:

https://chromium-review.googlesource.com/#/c/215780/5..6/arch/arm/boot/dts/rk3288-pinky-rev2.dts



At some point in time not too long after that got fixed.

It's unclear why the GPU is left enabled during suspend on the
mainline kernel.  Everything seems fine if I turn this off, so let's
do it.

Signed-off-by: Douglas Anderson <dianders@chromium.org>
Reviewed-by: Elaine Zhang <zhangqing@rock-chips.com>
Signed-off-by: Heiko Stuebner <heiko@sntech.de>