net: bridge: allow SW learn to take over HW fdb entries

Allow to take over an entry which was previously learned via HW when it
shows up from a SW port. This is analogous to how HW takes over SW learned
entries already.
Suggested-by: NRoopa Prabhu <roopa@cumulusnetworks.com>
Signed-off-by: NNikolay Aleksandrov <nikolay@cumulusnetworks.com>
Reviewed-by: NIdo Schimmel <idosch@mellanox.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

net/bridge/br_fdb.c

@@ -594,6 +594,9 @@ void br_fdb_update(struct net_bridge *br, struct net_bridge_port *source,
 				fdb->updated = now;
 			if (unlikely(added_by_user))
 				fdb->added_by_user = 1;
+			/* Take over HW learned entry */
+			if (unlikely(fdb->added_by_external_learn))
+				fdb->added_by_external_learn = 0;
 			if (unlikely(fdb_modified))
 				fdb_notify(br, fdb, RTM_NEWNEIGH);
 		}