soc: rockchip: power-domain: Fix wrong value when power up pd with writemask

Solve the pd could only ever turn off but never turn them on again,
if the pd registers have the writemask bits.

So far this affects the rk3328 only.

Fixes: 79bb17ce ("soc: rockchip: power-domain: Support domain control in hiword-registers")
Cc: stable@vger.kernel.org
Signed-off-by: Finley Xiao <finley.xiao@rock-chips.com>
Signed-off-by: Elaine Zhang <zhangqing@rock-chips.com>
Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Heiko Stuebner <heiko@sntech.de>