Socionext UniPhier SoC audio driver

The Socionext UniPhier audio subsystem consists of I2S and S/PDIF blocks in
the same register space.

Required properties:
- compatible      : should be one of the following:
		    "socionext,uniphier-ld11-aio"
		    "socionext,uniphier-ld20-aio"
		    "socionext,uniphier-pxs2-aio"
- reg             : offset and length of the register set for the device.
- interrupts      : should contain I2S or S/PDIF interrupt.
- pinctrl-names   : should be "default".
- pinctrl-0       : defined I2S signal pins for an external codec chip.
- clock-names     : should include following entries:
                    "aio"
- clocks          : a list of phandle, should contain an entry for each
                    entry in clock-names.
- reset-names     : should include following entries:
                    "aio"
- resets          : a list of phandle, should contain an entry for each
                    entry in reset-names.
- #sound-dai-cells: should be 1.

Optional properties:
- socionext,syscon: a phandle, should contain soc-glue.
                    The soc-glue is used for changing mode of S/PDIF signal pin
                    to Output from Hi-Z. This property is optional if you use
                    I2S signal pins only.

Example:
	audio {
		compatible = "socionext,uniphier-ld20-aio";
		reg = <0x56000000 0x80000>;
		interrupts = <0 144 4>;
		pinctrl-names = "default";
		pinctrl-0 = <&pinctrl_aout>;
		clock-names = "aio";
		clocks = <&sys_clk 40>;
		reset-names = "aio";
		resets = <&sys_rst 40>;
		#sound-dai-cells = <1>;

		socionext,syscon = <&sg>;
	};