net: bridge: notify on hw fdb takeover

Recently we added support for SW fdbs to take over HW ones, but that
results in changing a user-visible fdb flag thus we need to send a
notification, also it's consistent with how HW takes over SW entries.
Signed-off-by: NNikolay Aleksandrov <nikolay@cumulusnetworks.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

net/bridge/br_fdb.c

@@ -595,8 +595,10 @@ void br_fdb_update(struct net_bridge *br, struct net_bridge_port *source,
 			if (unlikely(added_by_user))
 				fdb->added_by_user = 1;
 			/* Take over HW learned entry */
-			if (unlikely(fdb->added_by_external_learn))
+			if (unlikely(fdb->added_by_external_learn)) {
 				fdb->added_by_external_learn = 0;
+				fdb_modified = true;
+			}
 			if (unlikely(fdb_modified))
 				fdb_notify(br, fdb, RTM_NEWNEIGH);
 		}