ice: Advertise supported link modes if none requested

User requested link modes affect what is returned as an advertised
link mode.  If no modes have been requested, we are not advertising
any link modes.  Advertise what we are capable of supporting if no
link modes have been requested.

Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>
Signed-off-by: Anirudh Venkataramanan <anirudh.venkataramanan@intel.com>
Tested-by: Andrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>