arm64: dts: rockchip: bring rk3399-firefly power-tree in line

The power-tree on the rk3399-firefly did not completely match the
documentation and vendor devicetree. It was also missing some
supply-hirarchy information and some regulator-gpio names did not
match the schematics. Fix this for the existing regulators before
introducing new things.

Signed-off-by: Heiko Stuebner <heiko@sntech.de>