Take avantage of the .set_mtu ethdev function and make it possible to configure
MTU on devices using testpmd.
Signed-off-by: Ivan Boule <ivan.boule@6wind.com>
Signed-off-by: David Marchand <david.marchand@6wind.com>
Acked-by: Konstantin Ananyev <konstantin.ananyev@intel.com>