ARM: dts: omap: remove unneeded unit name for sound nodes

This patch fixes the following DTC warning:

"sound@0 has a unit name, but no reg property"

Signed-off-by: Javier Martinez Canillas <javier@osg.samsung.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>
diff --git a/arch/arm/boot/dts/am57xx-beagle-x15.dts b/arch/arm/boot/dts/am57xx-beagle-x15.dts
index 0a5fc5d..75bd09b 100644
--- a/arch/arm/boot/dts/am57xx-beagle-x15.dts
+++ b/arch/arm/boot/dts/am57xx-beagle-x15.dts
@@ -151,7 +151,7 @@
 		};
 	};
 
-	sound0: sound@0 {
+	sound0: sound0 {
 		compatible = "simple-audio-card";
 		simple-audio-card,name = "BeagleBoard-X15";
 		simple-audio-card,widgets =