dt-bindings: add power-domain header for RK3368 SoCs

According to a description from TRM, add all the power domains.

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