ixgbe: Allow SFP+ on more than 82598 and 82599

Since SFP+ can be used with some X550 devices, permit them to be
detected.

Signed-off-by: Mark Rustad <mark.d.rustad@intel.com>
Tested-by: Phil Schmitt <phillip.j.schmitt@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>