ASoC: Disable automatic volume control in the CS4270 sound driver

Disable the automatic volume control feature of the CS4270 audio codec.  This
feature, which is enabled by default, causes volume change commands to be
delayed.  Sometimes the volume change happens after playback is started.

Signed-off-by: Timur Tabi <timur@freescale.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>