DT bindings for the R-/SH-Mobile irqpin controller

Required properties:

- compatible: has to be "renesas,intc-irqpin-<soctype>", "renesas,intc-irqpin"
  as fallback.
  Examples with soctypes are:
    - "renesas,intc-irqpin-r8a7740" (R-Mobile A1)
    - "renesas,intc-irqpin-r8a7778" (R-Car M1A)
    - "renesas,intc-irqpin-r8a7779" (R-Car H1)
    - "renesas,intc-irqpin-sh73a0" (SH-Mobile AG5)

- reg: Base address and length of each register bank used by the external
  IRQ pins driven by the interrupt controller hardware module. The base
  addresses, length and number of required register banks varies with soctype.
- interrupt-controller: Identifies the node as an interrupt controller.
- #interrupt-cells: has to be <2>: an interrupt index and flags, as defined in
  interrupts.txt in this directory.
- interrupts: Must contain a list of interrupt specifiers. For each interrupt
  provided by this irqpin controller instance, there must be one entry,
  referring to the corresponding parent interrupt.

Optional properties:

- any properties, listed in interrupts.txt, and any standard resource allocation
  properties
- sense-bitfield-width: width of a single sense bitfield in the SENSE register,
  if different from the default 4 bits
- control-parent: disable and enable interrupts on the parent interrupt
  controller, needed for some broken implementations
- clocks: Must contain a reference to the functional clock.  This property is
  mandatory if the hardware implements a controllable functional clock for
  the irqpin controller instance.
- power-domains: Must contain a reference to the power domain. This property is
  mandatory if the irqpin controller instance is part of a controllable power
  domain.


Example
-------

	irqpin1: interrupt-controller@e6900004 {
		compatible = "renesas,intc-irqpin-r8a7740",
			     "renesas,intc-irqpin";
		#interrupt-cells = <2>;
		interrupt-controller;
		reg = <0xe6900004 4>,
			<0xe6900014 4>,
			<0xe6900024 1>,
			<0xe6900044 1>,
			<0xe6900064 1>;
		interrupts = <0 149 IRQ_TYPE_LEVEL_HIGH
			      0 149 IRQ_TYPE_LEVEL_HIGH
			      0 149 IRQ_TYPE_LEVEL_HIGH
			      0 149 IRQ_TYPE_LEVEL_HIGH
			      0 149 IRQ_TYPE_LEVEL_HIGH
			      0 149 IRQ_TYPE_LEVEL_HIGH
			      0 149 IRQ_TYPE_LEVEL_HIGH
			      0 149 IRQ_TYPE_LEVEL_HIGH>;
		clocks = <&mstp2_clks R8A7740_CLK_INTCA>;
		power-domains = <&pd_a4s>;
	};