ASoC: SMDK: WM8994: Add device tree support for machine file

Add the basic device tree based lookup.

Signed-off-by: Padmavathi Venna <padma.v@samsung.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
diff --git a/arch/arm/boot/dts/exynos5250.dtsi b/arch/arm/boot/dts/exynos5250.dtsi
index fe05b60..a320b4a 100644
--- a/arch/arm/boot/dts/exynos5250.dtsi
+++ b/arch/arm/boot/dts/exynos5250.dtsi
@@ -269,7 +269,7 @@
 		#size-cells = <0>;
 	};
 
-	i2s@03830000 {
+	i2s0: i2s@03830000 {
 		compatible = "samsung,i2s-v5";
 		reg = <0x03830000 0x100>;
 		dmas = <&pdma0 10
@@ -282,7 +282,7 @@
 		samsung,idma-addr = <0x03000000>;
 	};
 
-	i2s@12D60000 {
+	i2s1: i2s@12D60000 {
 		compatible = "samsung,i2s-v5";
 		reg = <0x12D60000 0x100>;
 		dmas = <&pdma1 12
@@ -290,7 +290,7 @@
 		dma-names = "tx", "rx";
 	};
 
-	i2s@12D70000 {
+	i2s2: i2s@12D70000 {
 		compatible = "samsung,i2s-v5";
 		reg = <0x12D70000 0x100>;
 		dmas = <&pdma0 12