ARM: dts: Remove obsolete MIPI DPHY 'reg' property for exynos4

Since e4b3d380 ("phy: exynos-video-mipi: Fix regression by
adding support for PMU regmap") the Exynos PMU driver provides
regmap to access the MIPI DPHY registers. The MIPI DPHY node uses
a phandle to syscon to get this regmap. The 'reg' field is obsolete.
Signed-off-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
Reviewed-by: Javier Martinez Canillas <javier.martinez@collabora.co.uk>
Signed-off-by: Kukjin Kim <kgene@kernel.org>

arch/arm/boot/dts/exynos4.dtsi

@@ -78,7 +78,6 @@ chipid@10000000 {
 
 	mipi_phy: video-phy@10020710 {
 		compatible = "samsung,s5pv210-mipi-video-phy";
-		reg = <0x10020710 8>;
 		#phy-cells = <1>;
 		syscon = <&pmu_system_controller>;
 	};