dmaengine: idxd: add descs_completed field for completion record

dmaengine: idxd: add descs_completed field for completion record

The descs_completed field for a completion record is part of a batch
descriptor completion record. It takes the same location as bytes_completed
in a normal descriptor field. Add to expose to user.

Tested-by: Tony Zhu <tony.zhu@intel.com>
Signed-off-by: Dave Jiang <dave.jiang@intel.com>
Co-developed-by: Fenghua Yu <fenghua.yu@intel.com>
Signed-off-by: Fenghua Yu <fenghua.yu@intel.com>
Link: https://lore.kernel.org/r/20230407203143.2189681-11-fenghua.yu@intel.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>