ASoC: wm8960: 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/wm8960.txt

@@ -23,7 +23,7 @@ Optional properties:
 
 Example:
 
-codec: wm8960@1a {
+wm8960: codec@1a {
 	compatible = "wlf,wm8960";
 	reg = <0x1a>;