ixgbe: add new media type.

This patch adds support for a new media type fiber_fixed.  This is useful
to avoid all the SFP+ hot plug support path on devices who's fix fiber need
not worry about such things.  This patch is needed for a following patch
that adds support for "fiber_fixed" devices.

v2: cleaned up logging message based on feedback from David Miller

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