arm64: dts: rockchip: Add rk3568 PCIe2x1 controller

The PCIe2x1 controller is common between the rk3568 and rk3566. It is a
single lane PCIe2 compliant controller.

Signed-off-by: Peter Geis <pgwipeout@gmail.com>
Link: https://lore.kernel.org/r/20220429123832.2376381-5-pgwipeout@gmail.com


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