Renesas Watchdog Timer (WDT) Controller

Required properties:
 - compatible : Must be "renesas,<soctype>-wdt", followed by a generic
		fallback compatible string when compatible with the generic
		version.
	       Examples with soctypes are:
		 - "renesas,r8a7743-wdt" (RZ/G1M)
		 - "renesas,r8a7744-wdt" (RZ/G1N)
		 - "renesas,r8a7745-wdt" (RZ/G1E)
		 - "renesas,r8a77470-wdt" (RZ/G1C)
		The generic compatible string must be:
		 - "renesas,rcar-gen2-wdt" for R-Car Gen2 and RZ/G

  When compatible with the generic version, nodes must list the SoC-specific
  version corresponding to the platform first, followed by the generic
  version.

- reg : Should contain WDT registers location and length
- clocks : the clock feeding the watchdog timer.

Optional properties:
- timeout-sec : Contains the watchdog timeout in seconds
- power-domains : the power domain the WDT belongs to

Examples:

	rwdt: watchdog@e6020000 {
		compatible = "renesas,r8a7743-wdt",
			     "renesas,rcar-gen2-wdt";
		reg = <0 0xe6020000 0 0x0c>;
		clocks = <&mstp4_clks R8A7743_CLK_RWDT>;
		power-domains = <&cpg_clocks>;
		timeout-sec = <60>;
	};
