ASoC: sgtl5000: Make the node name generic

According to Devicetree Specification v0.2 document:

"The name of a node should be somewhat generic, reflecting the function
of the device and not its precise programming model."

Do as suggested in the binding example.
Signed-off-by: NFabio Estevam <fabio.estevam@nxp.com>
Signed-off-by: NMark Brown <broonie@kernel.org>

Documentation/devicetree/bindings/sound/sgtl5000.txt

@@ -39,7 +39,7 @@ VDDIO		1.8V		2.5V		3.3V
 
 Example:
 
-codec: sgtl5000@a {
+sgtl5000: codec@a {
 	compatible = "fsl,sgtl5000";
 	reg = <0x0a>;
 	#sound-dai-cells = <0>;