BACKPORT: UPSTREAM: Modify the __ufshcd_transfer_req_compl() documentation

Bring the __ufshcd_transfer_req_compl() documentation in sync with the
upstream documentation. See also upstream commit 73dc3c4a ("scsi: ufs:
Retry aborted SCSI commands instead of completing these successfully").

Bug: 204438323
(cherry picked from commit 73dc3c4a)
Change-Id: Ib412e0b88ba1e967f0fd486efec87d973f170f65
Signed-off-by: Bart Van Assche <bvanassche@google.com>