net/nfp: fix assigning port id in mbuf
net/nfp: fix assigning port id in mbuf

Although this can be done by the app, because other PMDs are doing it,
apps expect this behaviour from the PMD.

Fixes: b812daadad0d ("nfp: add Rx and Tx")
Cc: stable@dpdk.org

Signed-off-by: Alejandro Lucero <1ffca3a1926aae782ae3c39a5b308878ba1e5683@netronome.com>

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