ixgbe: Add SFP+ detection for X550 hardware

This patch is part of the future enablement of X550 SFP+ support.  This
HW uses different SDP so the interrupts need to be set up accordingly.

Signed-off-by: Donald C Skidmore <donald.c.skidmore@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>