dt-bindings: PCI: Convert Rockchip RK3399 PCIe to DT schema

Convert the Rockchip RK3399 PCIe Host/Endpoint controller to DT schema
format. Like most dual mode PCI controllers, we need to split the schema
into common, host and endpoint schemas.

Link: https://lore.kernel.org/r/20221219191209.1975834-1-robh@kernel.org


Signed-off-by: Rob Herring <robh@kernel.org>