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>