Hisilicon hix5hd2 gmac controller

Required properties:
- compatible: should be "hisilicon,hix5hd2-gmac".
- reg: specifies base physical address(s) and size of the device registers.
  The first region is the MAC register base and size.
  The second region is external interface control register.
- interrupts: should contain the MAC interrupt.
- #address-cells: must be <1>.
- #size-cells: must be <0>.
- phy-mode: see ethernet.txt [1].
- phy-handle: see ethernet.txt [1].
- mac-address: see ethernet.txt [1].
- clocks: clock phandle and specifier pair.

- PHY subnode: inherits from phy binding [2]

[1] Documentation/devicetree/bindings/net/ethernet.txt
[2] Documentation/devicetree/bindings/net/phy.txt

Example:
	gmac0: ethernet@f9840000 {
		compatible = "hisilicon,hix5hd2-gmac";
		reg = <0xf9840000 0x1000>,<0xf984300c 0x4>;
		interrupts = <0 71 4>;
		#address-cells = <1>;
		#size-cells = <0>;
		phy-mode = "mii";
		phy-handle = <&phy2>;
		mac-address = [00 00 00 00 00 00];
		clocks = <&clock HIX5HD2_MAC0_CLK>;

		phy2: ethernet-phy@2 {
			reg = <2>;
		};
	};
