arm64: dts: rockchip: Improve nanopi4 PCIe

Expand the power tree description with the 0V9 and 1V8 supplies to the
RK3399 PCIe block. The NanoPis M4 and NEO4 just route 2 lanes to the
user expansion pins, so there's not much more to say at the board level
for them; NanoPC-T4 has a standard M.2 connector so we can at least
claim the 3.3V supply to that too.

Signed-off-by: Robin Murphy <robin.murphy@arm.com>
Link: https://lore.kernel.org/r/a04a17f4b9b12e8698c76b34e7ca22f0c81845ce.1573908195.git.robin.murphy@arm.com


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