arm: dts: Use pmu_system_controller phandle for dp phy

DP PHY now require pmu-system-controller to handle PMU register
to control PHY's power isolation. Adding the same to dp-phy
node.

Signed-off-by: Vivek Gautam <gautam.vivek@samsung.com>
Reviewed-by: Jingoo Han <jg1.han@samsung.com>
Tested-by: Javier Martinez Canillas <javier.martinez@collabora.co.uk>
Signed-off-by: Kukjin Kim <kgene@kernel.org>
diff --git a/arch/arm/boot/dts/exynos5420.dtsi b/arch/arm/boot/dts/exynos5420.dtsi
index 517e50f..0ac5e08 100644
--- a/arch/arm/boot/dts/exynos5420.dtsi
+++ b/arch/arm/boot/dts/exynos5420.dtsi
@@ -503,8 +503,8 @@
 	};
 
 	dp_phy: video-phy@10040728 {
-		compatible = "samsung,exynos5250-dp-video-phy";
-		reg = <0x10040728 4>;
+		compatible = "samsung,exynos5420-dp-video-phy";
+		samsung,pmu-syscon = <&pmu_system_controller>;
 		#phy-cells = <0>;
 	};