i40e: Store the requested FEC information

Store information about FEC modes, that were requested. It will be used
in printing link status information function and this way there is no
need to call admin queue there.

Signed-off-by: Mariusz Stachura <mariusz.stachura@intel.com>
Tested-by: Andrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>