i40e: Remove 100M SGMII unless hw is X722

Only the X722 device now supports 100M SGMII, and nothing supports
100M on 1000Base_T.

Change-ID: I6f44dcd818944edd40041410e6de380f4a359a0c
Signed-off-by: Catherine Sullivan <catherine.sullivan@intel.com>
Signed-off-by: Shannon Nelson <shannon.nelson@intel.com>
Tested-by: Andrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>