arm: spear600: Add missing interrupt-parent of rtc

The interrupt-parent of rtc was missing, add it.

Fixes: 8113ba917d ("ARM: SPEAr: DT: Update device nodes")
Cc: stable@vger.kernel.org # v3.8+
Reported-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Olof Johansson <olof@lixom.net>

arch/arm/boot/dts/spear600.dtsi

@@ -194,6 +194,7 @@
 			rtc: rtc@fc900000 {
 				compatible = "st,spear600-rtc";
 				reg = <0xfc900000 0x1000>;
+				interrupt-parent = <&vic0>;
 				interrupts = <10>;
 				status = "disabled";
 			};