interface: fix the checksum offload in quad loop
interface: fix the checksum offload in quad loop

Type: fix

In quad loop, checksum will be calculated for all four packets,
if one packet needs checksum computation, without respecting their
respective flags. This patch fixes it.

Change-Id: I479b420ba0dcbd178ea4180bf05a0e55a6b13843
Signed-off-by: Mohsin Kazmi <3be96aed1fe21f963e790909e1d3a8e57ce776f2@cisco.com>

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