i40e: Report advertised link modes on 40GBASE_SR4

Defined the advertised link mode field for 40000baseSR4_Full for
use with ethtool.

Signed-off-by: Adam Ludkiewicz <adam.ludkiewicz@intel.com>
Tested-by: Andrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>