scsi: ufs: mcq: Add NULL check in ufshcd_mcq_abort()

In the Linux kernel, the following vulnerability has been resolved: scsi: ufs: mcq: Add NULL check in ufshcd_mcq_abort() A race can occur between the MCQ completion path and the abort handler: once a request completes, __blk_mq_free_request() sets rq->mq_hctx to NULL, meaning the subsequent ufshcd_mcq_req_to_hwq() call in ufshcd_mcq_abort() can return a NULL pointer. If this NULL pointer is dereferenced, the kernel will crash. Add a NULL check for the returned hwq pointer. If hwq is NULL, log an error and return FAILED, preventing a potential NULL-pointer dereference. As suggested by Bart, the ufshcd_cmd_inflight() check is removed. This is similar to the fix in commit 74736103fb41 ("scsi: ufs: core: Fix ufshcd_abort_one racing issue"). This is found by our static analysis tool KNighter.