app/testpmd: add L3 packet type in offload flags

app/testpmd: add L3 packet type in offload flags

As i40e PMD need to know the L3 packet type for TX checksum offloading,
the packet type has been added in rte_mbuf offload flags.

Signed-off-by: Helin Zhang <helin.zhang@intel.com>
Signed-off-by: Jing Chen <jing.d.chen@intel.com>
Acked-by: Cunming Liang <cunming.liang@intel.com>
Acked-by: Jijiang Liu <jijiang.liu@intel.com>
Acked-by: Jingjing Wu <jingjing.wu@intel.com>
Acked-by: Heqing Zhu <heqing.zhu@intel.com>
Tested-by: Waterman Cao <waterman.cao@intel.com>