dmaengine: ti-dma-crossbar: Add support for eDMA

The crossbar for eDMA works exactly the same way as sDMA, but sDMA
requires an offset of 1, while no offset is needed for eDMA.

Based on the patch from Misael Lopez Cruz <misael.lopez@ti.com>

Signed-off-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
CC: Misael Lopez Cruz <misael.lopez@ti.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>