If word 0x37 in the EEPROM is 0xFFFF _or_ 0x0000, then there is no
alternate MAC address in the EEPROM.
Signed-off-by: NBruce Allan <bruce.w.allan@intel.com>
Tested-by: NAaron Brown <aaron.f.brown@intel.com>
Signed-off-by: NJeff Kirsher <jeffrey.t.kirsher@intel.com>