scsi: ufs: Avoid potential lrb race caused by early release of lrb_in_use

There are still operations of lrbp after clearing lrb_in_use in
__ufshcd_transfer_req_compl. It may mess up the next task which takes
this lrbp in some corner cases. Hold lrb_in_use till all operations of
lrbp finished to avoid this potential race issue.

Change-Id: I4470d3596b7fedda0e791f35b22b1ca9864bbbfc
Signed-off-by: Ziqi Chen <ziqichen@codeaurora.org>