OMAP: Configure audio_mclk for twl4030-codec MFD

audio_mclk value is going to be handled by the
twl4030-codec MFD driver, configure the correct
value for boards, which is using the twl4030 audio.

Signed-off-by: Peter Ujfalusi <peter.ujfalusi@nokia.com>
Acked-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>