ASoC: imx: move eukrea audmux call into ASoC machine driver

It moves eukrea audmux configuration call from board file into ASoC
machine driver eukrea-tlv320, so that it gets aligned wm1133-ev1 and
mx27vis-aic32x4, and more importantly it will ease the moving of audmux
into sound/soc/imx as a platform driver later.

Signed-off-by: Shawn Guo <shawn.guo@linaro.org>
Acked-by: Sascha Hauer <s.hauer@pengutronix.de>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>