ASoC: fsl: Drop formats limitation for imx-pcm-dma.c

ASoC: fsl: Drop formats limitation for imx-pcm-dma.c

Now ASoC core is getting the intersection of supported formats not only
from CPU and CODEC dai's but also from DMA's. However, there should be
no specific width limitation from SDMA side.

So drop it. Otherwise, we would only support S16_LE format for all i.MX
platforms.

Signed-off-by: Nicolin Chen <Guangyu.Chen@freescale.com>
Signed-off-by: Mark Brown <broonie@linaro.org>
(cherry picked from commit e9ffb5ba4de17f14ca592e06a397c85541a72c7d)