When running testpmd in verbose mode on a NIC that uses the mlx5_core PMD, if
you send a packet with an invalid IP checksum it will show the ol_flag
`RTE_MBUF_F_RX_IP_CKSUM_UNKNOWN` when it should be
`RTE_MBUF_F_RX_IP_CKSUM_BAD`. According to lib/mbuf/rte_mbuf_core.h
`RTE_MBUF_F_RX_IP_CKSUM_UNKNOWN` should be shown when there is "no information
about the RX IP checksum" and `RTE_MBUF_F_RX_IP_CKSUM_BAD` should be shown when
"the IP checksum in the packet is wrong". This leads to an issue currently
where, from verbose output in testpmd, you cannot distinguish between a packet
having a bad checksum and one not being present at all. It should be noted that
this is also the case for L4 and OUTER_L4 checksums as well.

You can reproduce this by sending a scapy packet with the following structure
to the testpmd shell that is forwarding with verbose mode set to 1:

`pakt = Ether() / IP(chksum=0x0)`