* Marvell MMP Interrupt controller

Required properties:
- compatible : Should be "mrvl,mmp-intc", "mrvl,mmp2-intc" or
  "mrvl,mmp2-mux-intc"
- reg : Address and length of the register set of the interrupt controller.
  If the interrupt controller is intc, address and length means the range
  of the whold interrupt controller. If the interrupt controller is mux-intc,
  address and length means one register. Since address of mux-intc is in the
  range of intc. mux-intc is secondary interrupt controller.
- reg-names : Name of the register set of the interrupt controller. It's
  only required in mux-intc interrupt controller.
- interrupts : Should be the port interrupt shared by mux interrupts. It's
  only required in mux-intc interrupt controller.
- interrupt-controller : Identifies the node as an interrupt controller.
- #interrupt-cells : Specifies the number of cells needed to encode an
  interrupt source.
- mrvl,intc-nr-irqs : Specifies the number of interrupts in the interrupt
  controller.
- mrvl,clr-mfp-irq : Specifies the interrupt that needs to clear MFP edge
  detection first.

Example:
	intc: interrupt-controller@d4282000 {
		compatible = "mrvl,mmp2-intc";
		interrupt-controller;
		#interrupt-cells = <1>;
		reg = <0xd4282000 0x1000>;
		mrvl,intc-nr-irqs = <64>;
	};

	intcmux4@d4282150 {
		compatible = "mrvl,mmp2-mux-intc";
		interrupts = <4>;
		interrupt-controller;
		#interrupt-cells = <1>;
		reg = <0x150 0x4>, <0x168 0x4>;
		reg-names = "mux status", "mux mask";
		mrvl,intc-nr-irqs = <2>;
	};
