ARM: dts: at91: sama5d4: add watchdog interrupt property

The "interrupts" property is missing from the watchdog node. Add it with
highest priority value of 7.
Signed-off-by: Nicolas Ferre <nicolas.ferre@atmel.com>

arch/arm/boot/dts/sama5d4.dtsi

@@ -1302,6 +1302,7 @@ pit: timer@fc068630 {
 			watchdog@fc068640 {
 				compatible = "atmel,sama5d4-wdt";
 				reg = <0xfc068640 0x10>;
+				interrupts = <4 IRQ_TYPE_LEVEL_HIGH 7>;
 				clocks = <&clk32k>;
 				status = "disabled";
 			};