Marvell Armada 370 and Armada XP Interrupt Controller
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Required properties:
- compatible: Should be "marvell,mpic"
- interrupt-controller: Identifies the node as an interrupt controller.
- #interrupt-cells: The number of cells to define the interrupts. Should be 1.
  The cell is the IRQ number
- reg: Should contain PMIC registers location and length. First pair
  for the main interrupt registers, second pair for the per-CPU
  interrupt registers

Example:

        mpic: interrupt-controller@d0020000 {
              compatible = "marvell,mpic";
              #interrupt-cells = <1>;
              #address-cells = <1>;
              #size-cells = <1>;
              interrupt-controller;
              reg = <0xd0020000 0x1000>,
                    <0xd0021000 0x1000>;
        };