ARM: dts: add missing clock to MFC device for exynos4

sclk_mfc is required for MFC device since commit
0c227217 ("media: s5p-mfc: rename
special clock to sclk_mfc"), so add it to exynos4 dts.
Signed-off-by: NMarek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: NKukjin Kim <kgene.kim@samsung.com>

arch/arm/boot/dts/exynos4.dtsi

@@ -392,8 +392,8 @@
 		reg = <0x13400000 0x10000>;
 		interrupts = <0 94 0>;
 		samsung,power-domain = <&pd_mfc>;
-		clocks = <&clock CLK_MFC>;
-		clock-names = "mfc";
+		clocks = <&clock CLK_MFC>, <&clock CLK_SCLK_MFC>;
+		clock-names = "mfc", "sclk_mfc";
 		status = "disabled";
 	};