vxlan: __vxlan_fdb_delete(): Drop unused argument vid

This argument is necessary for vxlan_fdb_delete(), the API of which is
prescribed by ndo_fdb_del, but __vxlan_fdb_delete() doesn't need it.
Therefore drop it.

Signed-off-by: Petr Machata <petrm@mellanox.com>
Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>