ARM: dts: r8a7778: Add device node for RESET/WDT module

Add a device node for the RESET/WDT module, which provides a.o. reset
control, mode pin monitoring, and watchdog control.
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Acked-by: Dirk Behme <dirk.behme@de.bosch.com>

arch/arm/boot/dts/r8a7778.dtsi

@@ -626,4 +626,9 @@ R8A7778_CLK_SRU_SRC8
 				"sru-src6", "sru-src7", "sru-src8";
 		};
 	};
+
+	rst: reset-controller@ffcc0000 {
+		compatible = "renesas,r8a7778-reset-wdt";
+		reg = <0xffcc0000 0x40>;
+	};
 };