Loongson ls1x Interrupt Controller

Required properties:

- compatible : should be "loongson,ls1x-intc". Valid strings are:

- 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 2.
- interrupts : Specifies the CPU interrupt the controller is connected to.

Example:

intc: interrupt-controller@1fd01040 {
	compatible = "loongson,ls1x-intc";
	reg = <0x1fd01040 0x18>;

	interrupt-controller;
	#interrupt-cells = <2>;

	interrupt-parent = <&cpu_intc>;
	interrupts = <2>;
};