dpdk: TSO does not work for Cisco VIC
dpdk: TSO does not work for Cisco VIC

While TSO is supported for Intel NIC, Cisco VIC does not work.
The problem is due to txmode offloads is not properly set for
the Cisco VIC when enable-tcp-udp-checksum is configured.

Type: fix
Ticket: VPP-1838

Signed-off-by: Steven Luong <a748ea44ad7b179c2313a856d44e1e4eb39869bb@cisco.com>
Change-Id: I72c41db9b327ed8d08ef70d74e8cc6206d4a102f

chrisy/vpp,chrisy/vpp,chrisy/vpp,FDio/vpp,chrisy/vpp,FDio/vpp,FDio/vpp,chrisy/vpp,FDio/vpp,chrisy/vpp,FDio/vpp,chrisy/vpp,FDio/vpp,FDio/vpp,FDio/vpp,chrisy/vpp