scsi: ufs: core: Add NULL check in ufshcd_mcq_compl_pending_transfer()

scsi: ufs: core: Add NULL check in ufshcd_mcq_compl_pending_transfer()

Add a NULL check for the returned hwq pointer by ufshcd_mcq_req_to_hwq().

This is similar to the fix in commit 74736103fb41 ("scsi: ufs: core: Fix
ufshcd_abort_one racing issue").

Signed-off-by: Chenyuan Yang <chenyuan0y@gmail.com>
Link: https://lore.kernel.org/r/20250412195909.315418-1-chenyuan0y@gmail.com
Fixes: ab248643d3d6 ("scsi: ufs: core: Add error handling for MCQ mode")
Reviewed-by: Peter Wang <peter.wang@mediatek.com>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>