igb: Enable media autosense for the i350.

This patch enables the hardware feature "Media Auto Sense" also on the
i350. It works in the same way as on the 82850 devices. Hardware designs
using dual PHYs (fiber/copper) can enable this feature by setting the MAS
enable bits in the NVM_COMPAT register (0x03) in the EEPROM.

Signed-off-by: Manfred Rudigier <manfred.rudigier@omicronenergy.com>
Tested-by: Aaron Brown <aaron.f.brown@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>