net/pcap: fix Rx with small buffers
net/pcap: fix Rx with small buffers

If the pkt pool contains only buffers smaller than the default headroom,
then the driver will compute an invalid buffer size (negative value cast
to an uint16_t).
Rely on the mbuf api to check how much space is available in the mbuf.

Fixes: 6eb0ae218a98 ("pcap: fix mbuf allocation")
Cc: stable@dpdk.org

Signed-off-by: David Marchand <f28529695cfa9e3e1eb84e7072aa626af4abb18e@redhat.com>
Acked-by: Ferruh Yigit <ba8734c3c506d2e3557bd4ac8fdaccd25bdb9aa7@intel.com>

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