ethdev: update description of port name
ethdev: update description of port name

Change adds extra information on name parameter for API
rte_eth_dev_get_name_by_port and rte_eth_dev_get_port_by_name.

Signed-off-by: Vipin Varghese <b0b9508e3fd3e721e16f75bda9fcfd493661c711@intel.com>
Reviewed-by: Ferruh Yigit <ba8734c3c506d2e3557bd4ac8fdaccd25bdb9aa7@intel.com>

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