bridge: netlink: add fdb flush

Simple attribute that flushes the bridge's fdb.

Signed-off-by: Nikolay Aleksandrov <nikolay@cumulusnetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/bridge/br_netlink.c

@@ -859,6 +859,9 @@ static int br_changelink(struct net_device *brdev, struct nlattr *tb[],
 		br_recalculate_fwd_mask(br);
 	}
 
+	if (data[IFLA_BR_FDB_FLUSH])
+		br_fdb_flush(br);
+
 	return 0;
 }