app/testpmd: compute checksum in ICMP reply
app/testpmd: compute checksum in ICMP reply

ICMP echo replies with invalid checksums may be dropped by network nodes or
ignored by the ping utility.

Signed-off-by: Adrien Mazarguil <9d39ea493ca46c560334f650ac5d4b5ffbcb5cf0@6wind.com>
Acked-by: Ivan Boule <8408c61bea57ac94dd0d4dac44b115be1b288952@6wind.com>

msune/dpdk,tsphillips/dpdk-fork,mixja/dpdk,venkynv/dpdk-mirror,john-mcnamara-intel/dpdk,mixja/dpdk,msune/dpdk,tsphillips/dpdk-fork,venkynv/dpdk-mirror,john-mcnamara-intel/dpdk,mixja/dpdk,msune/dpdk,venkynv/dpdk-mirror,venkynv/dpdk-mirror,john-mcnamara-intel/dpdk,tsphillips/dpdk-fork,mixja/dpdk,msune/dpdk,tsphillips/dpdk-fork,john-mcnamara-intel/dpdk