bonding: fix name and port validation

bonding: fix name and port validation

Cleanup the code in bonding that checks ports.
  * Use standard rte_eth_dev_is_valid_port
  * Change name of driver string to avoid variable namespace conflicts
  * Get rid of unnecessary string comparison stuff. A simple pointer
    check is enough here.
  * Get rid of unnecessary assignment of driver_name, it is already
    done by common code.
  * Don't generate unnecessary log messages on error.

Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>
Acked-by: Declan Doherty <declan.doherty@intel.com>