Commit 42810d (ASoC: imx-mc13783: Add audmux settings for mx27pdk) broke
the sound on mx31moboard. Restore back the audmux setting on such boards.
Signed-off-by: NPhilippe Rétornaz <philippe.retornaz@epfl.ch>
Signed-off-by: NMark Brown <broonie@linaro.org>