dmaengine: vdma: Add config structure to differentiate dmas

This patch adds config structure in the driver to differentiate
AXI DMA's and to add more features(clock support etc..) to these DMA's.

Signed-off-by: Kedareswara rao Appana <appanad@xilinx.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>