app/testpmd: check MAC address query
app/testpmd: check MAC address query

This patch checks return value for rte_eth_dev_info_get() in show_macs().

Coverity issue: 353629
Fixes: e1d44d0ad623 ("app/testpmd: show MAC addresses added to a port")
Cc: stable@dpdk.org

Signed-off-by: Kalesh AP <818b6a3caba85cc3a76890be15484140b8e9f23b@broadcom.com>
Acked-by: Xiaoyun Li <151cc00bdba86cfa2ecfc39aaa98def8f092d9d8@intel.com>
Acked-by: Andrew Rybchenko <4155e7bf8e0185127625dac6d84336299844982f@oktetlabs.ru>

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