arm64: dts: rockchip: add PCIe3 support for rk3588

Add both PCIe3 controllers together with the shared PHY.

Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>
Link: https://lore.kernel.org/r/20230717173512.65169-3-sebastian.reichel@collabora.com


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