dmaengine: ti-dma-crossbar: Make idr xbar instance-specific

In preparation for supporting multiple DMA crossbar instances,
make the idr xbar instance specific.

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