UPSTREAM: dt-bindings: modify document of Rockchip power domains

UPSTREAM: dt-bindings: modify document of Rockchip power domains

Modify binding documentation for the power domains
found on Rockchip RK3368 SoCs.

Signed-off-by: zhangqing <zhangqing@rock-chips.com>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Heiko Stuebner <heiko@sntech.de>
(cherry picked from git://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git
master commit 1f164bd5b7dd4a1903c274ca70bf1ab11684db99)

Change-Id: Id6ef1ecfb32ee92e3a339326c1354a60b9028a80
Signed-off-by: Elaine Zhang <zhangqing@rock-chips.com>