ARM: dts: Use labels for overriding nodes in exynos5440 boards

Usage of labels instead of full paths reduces possible mistakes when
overriding nodes.

Signed-off-by: Krzysztof Kozlowski <k.kozlowski.k@gmail.com>
Signed-off-by: Kukjin Kim <kgene@kernel.org>
diff --git a/arch/arm/boot/dts/exynos5440-sd5v1.dts b/arch/arm/boot/dts/exynos5440-sd5v1.dts
index 268609a..a98501b 100644
--- a/arch/arm/boot/dts/exynos5440-sd5v1.dts
+++ b/arch/arm/boot/dts/exynos5440-sd5v1.dts
@@ -27,13 +27,13 @@
 		};
 	};
 
-	gmac: ethernet@00230000 {
-		fixed_phy;
-		phy_addr = <1>;
-	};
-
 	spi {
 		status = "disabled";
 	};
 
 };
+
+&gmac {
+	fixed_phy;
+	phy_addr = <1>;
+};