Cirrus Logic Madera class audio codec IRQ driver

See also the core bindings for the parent MFD driver:
See Documentation/devicetree/bindinge/mfd/madera.txt

Required properties:

  - interrupts : The interrupt line the /IRQ signal for the device is
    connected to.

  - interrupt-controller : Madera class devices contain interrupt controllers
    and may provide interrupt services to other devices.

  - interrupt-parent : The parent interrupt controller.

  - #interrupt-cells: the number of cells to describe an IRQ, this should be 2.
    The first cell is the IRQ number.
    The second cell is the flags, encoded as the trigger masks from
    bindings/interrupt-controller/interrupts.txt

Optional properties:
  - cirrus,irq-gpios : The GPIO the host IRQ is connected to. Used when the
    host IRQ is edge-triggered to emulate a level-triggered IRQ. If specified
    must be exactly one GPIO entry

  - cirrus,irq_flags :  host controller flags as defined in
    bindings/interrupt-controller/interrupts.txt

Example:

codec: cs47l85@0 {
	compatible = "cirrus,cs47l85";

	interrupts = <&host_irq1>;
	interrupt-controller;
	#interrupt-cells = <2>;
        interrupt-parent = <&gic>;
};