* Allwinner A10 MDIO Ethernet Controller interface

Required properties:
- compatible: should be "allwinner,sun4i-mdio".
- reg: address and length of the register set for the device.

Optional properties:
- phy-supply: phandle to a regulator if the PHY needs one

Example at the SoC level:
mdio@01c0b080 {
	compatible = "allwinner,sun4i-mdio";
	reg = <0x01c0b080 0x14>;
	#address-cells = <1>;
	#size-cells = <0>;
};

And at the board level:

mdio@01c0b080 {
	phy-supply = <&reg_emac_3v3>;

	phy0: ethernet-phy@0 {
		reg = <0>;
	};
};