WM8974 audio CODEC

This device supports both I2C and SPI (configured with pin strapping
on the board).

Required properties:
  - compatible: "wlf,wm8974"
  - reg: the I2C address or SPI chip select number of the device

Examples:

codec: wm8974@1a {
	compatible = "wlf,wm8974";
	reg = <0x1a>;
};
