ARM: dts: Update video-phy node with syscon phandle for exynos3250

As a follow-up to recent changes to Exynos mipi video phy driver,
introducing support for PMU regmap in commit e4b3d38088df ("phy:
exynos-video-mipi: Fix regression by adding support for PMU regmap")
add a syscon phandle to video-phy node to bring back to life both
MIPI DSI display and MIPI CSIS-2 camera sensor on Exynos3250.

Signed-off-by: Beata Michalska <b.michalska@samsung.com>
Reviewed-by: Javier Martinez Canillas <javier.martinez@collabora.co.uk>
Signed-off-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
Signed-off-by: Kukjin Kim <kgene@kernel.org>

arch/arm/boot/dts/exynos3250.dtsi

@@ -138,8 +138,8 @@
 
 		mipi_phy: video-phy@10020710 {
 			compatible = "samsung,s5pv210-mipi-video-phy";
-			reg = <0x10020710 8>;
 			#phy-cells = <1>;
+			syscon = <&pmu_system_controller>;
 		};
 
 		pd_cam: cam-power-domain@10023C00 {