examples/ip_reassembly: enable IP checksum offload
examples/ip_reassembly: enable IP checksum offload

As per the documentation to use any IP offload features, application
must set required offload flags into mbuf->ol_flags.

Signed-off-by: Sunil Kumar Kori <bdee174bc83e2fb76d979ba14c67b948a0d67de5@marvell.com>
Acked-by: Konstantin Ananyev <cbd5212b59ab42a210d72992d23a3aa17cfd3eaf@intel.com>

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