ASoC: cs42xx8: 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/cs42xx8.txt

@@ -16,7 +16,7 @@ Required properties:
 
 Example:
 
-codec: cs42888@48 {
+cs42888: codec@48 {
 	compatible = "cirrus,cs42888";
 	reg = <0x48>;
 	clocks = <&codec_mclk 0>;