arm64: dts: r8a7796: Add RWDT node

Add a device node for the Watchdog Timer (WDT) controller on the Renesas
R-Car M3-W (r8a7796) SoC.
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Acked-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>

arch/arm64/boot/dts/renesas/r8a7796.dtsi

@@ -98,6 +98,15 @@ timer {
 					(GIC_CPU_MASK_SIMPLE(1) | IRQ_TYPE_LEVEL_LOW)>;
 		};
 
+		wdt0: watchdog@e6020000 {
+			compatible = "renesas,r8a7796-wdt",
+				     "renesas,rcar-gen3-wdt";
+			reg = <0 0xe6020000 0 0x0c>;
+			clocks = <&cpg CPG_MOD 402>;
+			power-domains = <&sysc R8A7796_PD_ALWAYS_ON>;
+			status = "disabled";
+		};
+
 		cpg: clock-controller@e6150000 {
 			compatible = "renesas,r8a7796-cpg-mssr";
 			reg = <0 0xe6150000 0 0x1000>;