ROCKCHIP multicodecs audio

Required properties:
- compatible: "rockchip,multicodecs-card"
- rockchip,cpu: The phandle of the Rockchip I2S/PDM controller that's
  connected to the CODEC
- rockchip,codec: The phandle of audio codecs

Example:

sound {
	compatible = "rockchip,multicodecs-card";
	rockchip,cpu = <&i2s0_8ch>;
	rockchip,codec = <&codec>, <&vad>;
};