ARM: dts: Add rk808 PMIC to rk3288-evb-rk808

This adds initial support.  For now, regulators are always on and we
don't specify the input supply for all of the regulators.

Signed-off-by: huang lin <hl@rock-chips.com>
Signed-off-by: Doug Anderson <dianders@chromium.org>
Signed-off-by: Heiko Stuebner <heiko@sntech.de>