macvlan fdb replace support

Add support for iproute2 command 'bridge fdb replace ...'.
The rtnletlink call back function ndo_fdb_add will be called
with the NLM_F_REPLACE flag set.
Simply return -EOPNOTSUP.

Resubmitted because net-next was closed last week.
Signed-off-by: Thomas Richter <tmricht@linux.vnet.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/macvlan.c

@@ -597,6 +597,9 @@ static int macvlan_fdb_add(struct ndmsg *ndm, struct nlattr *tb[],
 	if (!vlan->port->passthru)
 		return -EOPNOTSUPP;
 
+	if (flags & NLM_F_REPLACE)
+		return -EOPNOTSUPP;
+
 	if (is_unicast_ether_addr(addr))
 		err = dev_uc_add_excl(dev, addr);
 	else if (is_multicast_ether_addr(addr))