scsi: target_core_user: fix double unlock

The caller of queue_cmd_ring grabs and releases the lock, so the
tcmu_setup_cmd_timer failure handling inside queue_cmd_ring should not call
mutex_unlock.
Signed-off-by: Mike Christie <mchristi@redhat.com>
Reviewed-by: Xiubo Li <xiubli@redhat.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

drivers/target/target_core_user.c

@@ -1066,7 +1066,6 @@ static sense_reason_t queue_cmd_ring(struct tcmu_cmd *tcmu_cmd, int *scsi_err)
 				   &udev->cmd_timer);
 	if (ret) {
 		tcmu_cmd_free_data(tcmu_cmd, tcmu_cmd->dbi_cnt);
-		mutex_unlock(&udev->cmdr_lock);
 
 		*scsi_err = TCM_OUT_OF_RESOURCES;
 		return -1;