* Allwinner EMAC ethernet controller

Required properties:
- compatible: should be "allwinner,sun4i-emac".
- reg: address and length of the register set for the device.
- interrupts: interrupt for the device
- phy: A phandle to a phy node defining the PHY address (as the reg
  property, a single integer).
- clocks: A phandle to the reference clock for this device

Optional properties:
- (local-)mac-address: mac address to be used by this driver

Example:

emac: ethernet@01c0b000 {
       compatible = "allwinner,sun4i-emac";
       reg = <0x01c0b000 0x1000>;
       interrupts = <55>;
       clocks = <&ahb_gates 17>;
       phy = <&phy0>;
};