soc: rockchip: power-domain: Modify power domain driver for rk3368

This driver is modified to support RK3368 SoC.

Signed-off-by: zhangqing <zhangqing@rock-chips.com>
Reviewed-by: Caesar Wang <wxt@rock-chips.com>
Signed-off-by: Heiko Stuebner <heiko@sntech.de>