* Broadcom UniMAC MDIO bus controller

Required properties:
- compatible: should be "brcm,unimac-mdio"
- reg: address and length of the regsiter set for the device, first one is the
  base register, and the second one is optional and for indirect accesses
- reg-names: name(s) of the register must be "mdio" and optional "mdio_indir_rw"
- #size-cells: must be 1
- #address-cells: must be 0

Optional properties:
- interrupts: must be two interrupts, one for MDIO done, one for MDIO error
- interrupt-names: must be "mdio_done" for the first interrupt and "mdio_error"
  for the second

Child nodes of this MDIO bus controller node are standard Ethernet PHY device
nodes as described in Documentation/devicetree/bindings/net/phy.txt

Example:

mdio@403c0 {
	compatible = "brcm,unimac-mdio";
	reg = <0x403c0 0x8 0x40300 0x18>;
	reg-names = "mdio", "mdio_indir_rw";
	#size-cells = <1>;
	#address-cells = <0>;

	...
	phy@0 {
		compatible = "ethernet-phy-ieee802.3-c22";
		reg = <0>;
	};
};