The codec chip has a physical MUTE pin to let users control it via
GPIO. So this patch add a mute control support to the driver.
Signed-off-by: NNicolin Chen <nicoleotsuka@gmail.com>
Acked-by: NPaul Handrigan <Paul.Handrigan@cirrus.com>
Signed-off-by: NMark Brown <broonie@kernel.org>