net/pcap: fix argument checks

net/pcap: fix argument checks

Previously rx/tx_queues were passed into eth_from_pcaps_common()
as ptrs and were checked for being NULL.

In commit da6ba28f0540 ("net/pcap: use a struct to pass user options")
that changed to pass in a ptr to a pmd_devargs_all which contains
the rx/tx_queues.

The parameter checking was not updated as part of that commit and
coverity caught that there was still a check if rx/tx_queues were
NULL, apparently after they had been dereferenced.

In fact as they are a members of the devargs_all struct, they will
not be NULL so remove those checks.

1231        struct pmd_devargs *rx_queues = &devargs_all->rx_queues;
1232        struct pmd_devargs *tx_queues = &devargs_all->tx_queues;
1233        const unsigned int nb_rx_queues = rx_queues->num_of_queue;
    deref_ptr: Directly dereferencing pointer tx_queues.
1234        const unsigned int nb_tx_queues = tx_queues->num_of_queue;
1235        unsigned int i;
1236
1237        /* do some parameter checking */
    CID 345004: Dereference before null check (REVERSE_INULL)
    [select issue]
1238        if (rx_queues == NULL && nb_rx_queues > 0)
1239                return -1;
    CID 345029 (#1 of 1): Dereference before null check (REVERSE_INULL)
    check_after_deref: Null-checking tx_queues suggests that it may be
    null, but it has already been dereferenced on all paths leading to
    the check.
1240        if (tx_queues == NULL && nb_tx_queues > 0)
1241                return -1;

Coverity issue: 345029
Coverity issue: 345044
Fixes: da6ba28f0540 ("net/pcap: use a struct to pass user options")
Cc: stable@dpdk.org
Signed-off-by: Kevin Traynor <ktraynor@redhat.com>
Acked-by: Cian Ferriter <cian.ferriter@intel.com>