qcacmn: Do not call stats_cb after vdev is deleted

Currently before calling the stats_cbk we do not
check if the vdev has been deleted or not. There is
a case where vdev might be deleted (but not freed due
to pending ref-count) and the osif_vdev will be freed
as a part of the delete sequence. In this case, calling
stats_cbk with dangling pointer to osif_vdev will lead
to an access to memory which has been freed.

To mitigate this issue, check if the vdev has been marked
for deletion, before calling the stats_cbk in tx completion
path.

Change-Id: I32ef68f45f172fc903ab597a62bb4b3e3cb0f574
CRs-Fixed: 3635454

dp/wifi3.0/dp_tx.c

@@ -5743,8 +5743,7 @@ void dp_tx_update_connectivity_stats(struct dp_soc *soc,
 
 	qdf_assert(tx_desc);
 
-	if (!vdev ||
-	    !vdev->osif_vdev ||
+	if (!vdev || vdev->delete.pending || !vdev->osif_vdev ||
 	    !vdev->stats_cb)
 		return;