ASoC: omap-pcm, omap-dmic: Change the use of omap_pcm_dma_data->data_type

Instead of the OMAP DMA data type definition the data_type will be used to
specify the number of bits the DMA word should be configured or 0 in case
when based on the stream's format the omap-pcm can decide the needed DMA
word size.
This feature is needed for the omap-hdmi where the sDMA need to be
configured for 32bit word type regardless of the audio format used.

Signed-off-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
Tested-by: Janusz Krzysztofik <jkrzyszt@tis.icnet.pl>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>