commit c4204960 upstream.

snd_soc_dapm_sync takes the dapm_mutex internally, but we currently take
it externally as well. This patch fixes this.
Signed-off-by: Charles Keepax <ckeepax@opensource.wolfsonmicro.com>
Signed-off-by: Mark Brown <broonie@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>