ASoC: omap: Introduce the generic_dmaengine_pcm based sdma-pcm

ASoC: omap: Introduce the generic_dmaengine_pcm based sdma-pcm

With the generic dmaengine_pcm support the omap-cpm can be replaced with a
much smaller wrapper.

CPU DAI drivers can use the:
int sdma_pcm_platform_register(struct device *dev,
			       char *txdmachan, char *rxdmachan);

To register the platform driver, txdmachan/rxdmachan is only needed to be
provided if the DMA channel names are not standard tx/rx, like in case of
McPDM, or the DAI is only capable of one audio direction (DMIC, HDMI).

This patch only introduces the source file and changes to the
Kconfig/Makefile, but does not change any of the DAI drivers to use it.

Signed-off-by: Peter Ujfalusi <[email protected]>
Acked-by: Jarkko Nikula <[email protected]>
Signed-off-by: Mark Brown <[email protected]>