doc: fix typo in pcap guide
doc: fix typo in pcap guide

Changed "net_pcap1;" to "net_pcap1," in order to make the command
correct.

Fixes: 53bf48403409 ("net/pcap: capture only ingress packets from Rx iface")
Cc: stable@dpdk.org

Signed-off-by: Sarosh Arif <701b58c7cb2b006b3a7612646904b47eba236db5@emumba.com>
Reviewed-by: Ferruh Yigit <ba8734c3c506d2e3557bd4ac8fdaccd25bdb9aa7@intel.com>

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