dmaengine: edma: Add support for DMA_PAUSE/RESUME operation

Pause/Resume can be used by the audio stack when the stream is paused/resumed
The edma platform code has support for this and the legacy audio stack used
this.

Signed-off-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
Acked-by: Joel Fernandes <joelf@ti.com>
Reviewed-and-Tested-by: Joel Fernandes <joelf@ti.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>