This patch adds MTU default value to qmap network interface in
order to avoid "RTNETLINK answers: No buffer space available"
error when setting an ipv6 address.
Signed-off-by: Daniele Palmas <dnlplm@gmail.com> Acked-by: Bjørn Mork <bjorn@mork.no> Signed-off-by: David S. Miller <davem@davemloft.net>