The segment list in a descriptor should be checked for empty, else
it will try to access invalid address for the first call.  This
patch fixes this issue.
Signed-off-by: NSrikanth Thokala <sthokal@xilinx.com>
Signed-off-by: NMichal Simek <michal.simek@xilinx.com>
Signed-off-by: NVinod Koul <vinod.koul@intel.com>