Added basic clock support for axi dma's.
The clocks are requested at probe and released at remove.
Reviewed-by: NShubhrajyoti Datta <shubhraj@xilinx.com>
Signed-off-by: NKedareswara rao Appana <appanad@xilinx.com>
Signed-off-by: NVinod Koul <vinod.koul@intel.com>