examples/ipsec-secgw: update mbuf packet type
examples/ipsec-secgw: update mbuf packet type

Packet_type should be updated to remove/add L4 type for
encrypted/decrypted packet

Signed-off-by: Akhil Goyal <74d7c4c993a22c1d4f60c46ff3d95c969a24a25c@nxp.com>
Acked-by: Radu Nicolau <fa459cf59d47c122ba776e9a6f631c862bf44680@intel.com>

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