ARM: dts: Add node for GMAC for exynos5440

This patch adds node for GMAC for exynos5440 SoC supported by GMAC
driver.

Signed-off-by: Byungho An <bh74.an@samsung.com>
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>

arch/arm/boot/dts/exynos5440.dtsi

@@ -147,6 +147,17 @@
 		clock-names = "watchdog";
 	};
 
+	gmac: ethernet@00230000 {
+		compatible = "snps,dwmac-3.70a";
+		reg = <0x00230000 0x8000>;
+		interrupt-parent = <&gic>;
+		interrupts = <0 31 4>;
+		interrupt-names = "macirq";
+		phy-mode = "sgmii";
+		clocks = <&clock 12>;
+		clock-names = "stmmaceth";
+	};
+
 	amba {
 		#address-cells = <1>;
 		#size-cells = <1>;