scsi: qedf: Fix null ptr reference in qedf_stag_change_work

Link: https://lore.kernel.org/r/20200824033436.45570-1-yebin10@huawei.com
Acked-by: Saurav Kashyap <skashyap@marvell.com>
Signed-off-by: Ye Bin <yebin10@huawei.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

drivers/scsi/qedf/qedf_main.c

@@ -3863,7 +3863,7 @@ void qedf_stag_change_work(struct work_struct *work)
 	    container_of(work, struct qedf_ctx, stag_work.work);
 
 	if (!qedf) {
-		QEDF_ERR(&qedf->dbg_ctx, "qedf is NULL");
+		QEDF_ERR(NULL, "qedf is NULL");
 		return;
 	}
 	QEDF_ERR(&qedf->dbg_ctx, "Performing software context reset.\n");