Broadcom BCM7120 Level 2 interrupt controller

Required properties:

- compatible: should be "brcm,bcm7120-l2-intc"
- reg: specifies the 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, should be 1.
- interrupt-parent: specifies the phandle to the parent interrupt controller
  this one is cascaded from
- interrupts: specifies the interrupt line(s) in the interrupt-parent domain
  to be used for cascading
- brcm,int-map-mask: 32-bits bit mask describing how the interrupts at this level
  map to their respective parents. Should match exactly the number of interrupts
  specified in the 'interrupts' property.

Optional properties:

- brcm,irq-can-wake: if present, this means the L2 controller can be used as a
  wakeup source for system suspend/resume.

- brcm,int-fwd-mask: if present, a 32-bits bit mask describing the interrupts
  which need to be enabled in this controller to flow to the higher level
  interrupt controller.

Example:

irq0_intc: interrupt-controller@f0406800 {
	compatible = "brcm,bcm7120-l2-intc";
	interrupt-parent = <&intc>;
	#interrupt-cells = <1>;
	reg = <0xf0406800 0x8>;
	interrupt-controller;
	interrupts = <0x0 0x42 0x0>, <0x0 0x40 0x0>;
	interrupt-names = "upg_main", "upg_bsc";
	brcm,int-map-mask = <0xeb8>, <0x140>;
	brcm,int-fwd-mask = <0x7>;
};