ARM: dts: exynos: Add missing interrupt-controller properties to Exynos5410 PMU

PMU (system-controller@10040000) is used as interrupt-parent for certain
nodes thus it should be marked as interrupt-controller to silence
warnings when building Exynos5410-based DTBs:

  arch/arm/boot/dts/exynos5410-odroidxu.dtb: Warning (interrupts_property):
    Missing interrupt-controller or interrupt-map property in /soc/system-controller@10040000
  arch/arm/boot/dts/exynos5410-odroidxu.dtb: Warning (interrupts_property):
    Missing #interrupt-cells in interrupt-parent /soc/system-controller@10040000
Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>

arch/arm/boot/dts/exynos5410.dtsi

@@ -75,6 +75,9 @@ pmu_system_controller: system-controller@10040000 {
 			clock-names = "clkout16";
 			clocks = <&fin_pll>;
 			#clock-cells = <1>;
+			interrupt-controller;
+			#interrupt-cells = <3>;
+			interrupt-parent = <&gic>;
 		};
 
 		clock: clock-controller@10010000 {