net/vmxnet3: add speed capability
net/vmxnet3: add speed capability

Signed-off-by: Ido Barnea <3a6e28cf60eb2f9d9d6e5ab6275926d9a599fe66@cisco.com>
Acked-by: Yong Wang <0cd1be787884a033c98e298059e386114d22793e@vmware.com>

john-mcnamara-intel/dpdk,john-mcnamara-intel/dpdk,john-mcnamara-intel/dpdk,john-mcnamara-intel/dpdk