Allwinner Sunxi Interrupt Controller

Required properties:

- compatible : should be "allwinner,sun4i-ic"
- reg : Specifies base physical address and size of the registers.
- interrupt-controller : Identifies the node as an interrupt controller
- #interrupt-cells : Specifies the number of cells needed to encode an
  interrupt source. The value shall be 1.

Example:

intc: interrupt-controller {
	compatible = "allwinner,sun4i-ic";
	reg = <0x01c20400 0x400>;
	interrupt-controller;
	#interrupt-cells = <2>;
};
