ARM: at91: at91sam9n12ek: switch sound to CCF

As the at91sam9n12ek has switch to CCF, so add clock for wm8904

Signed-off-by: Bo Shen <voice.shen@atmel.com>
Reviwed-by: Mark Brown <broonie@linaro.org>
Signed-off-by: Nicolas Ferre <nicolas.ferre@atmel.com>

arch/arm/boot/dts/at91sam9n12ek.dts

@@ -56,6 +56,8 @@
 				wm8904: codec@1a {
 					compatible = "wm8904";
 					reg = <0x1a>;
+					clocks = <&pck0>;
+					clock-names = "mclk";
 				};
 
 				qt1070: keyboard@1b {