ixgbe: Complete support for X553 sgmii

The initial patches supporting X553 sgmii forgot some details.  This patch
should cover those missing spots.

Signed-off-by: Don Skidmore <donald.c.skidmore@intel.com>
Tested-by: Krishneil Singh <krishneil.k.singh@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>