dmaengine: xilinx_dma: Free BD consistent memory

Free BD consistent memory while freeing the channel
i.e in free_chan_resources.

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