[SCSI] mvsas: fix potential NULL dereference

Stanse found that in mvs_abort_task, mvi_dev is dereferenced earlier
than tested for being NULL. Move the assignment below the test.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: James Bottomley <James.Bottomley@suse.de>

drivers/scsi/mvsas/mv_sas.c

@@ -1640,7 +1640,7 @@ int mvs_abort_task(struct sas_task *task)
 	struct mvs_tmf_task tmf_task;
 	struct domain_device *dev = task->dev;
 	struct mvs_device *mvi_dev = (struct mvs_device *)dev->lldd_dev;
-	struct mvs_info *mvi = mvi_dev->mvi_info;
+	struct mvs_info *mvi;
 	int rc = TMF_RESP_FUNC_FAILED;
 	unsigned long flags;
 	u32 tag;
@@ -1650,6 +1650,8 @@ int mvs_abort_task(struct sas_task *task)
 		rc = TMF_RESP_FUNC_FAILED;
 	}
 
+	mvi = mvi_dev->mvi_info;
+
 	spin_lock_irqsave(&task->task_state_lock, flags);
 	if (task->task_state_flags & SAS_TASK_STATE_DONE) {
 		spin_unlock_irqrestore(&task->task_state_lock, flags);