i40evf: disable unused flags

The i40evf hardware doesn't have any way to ever report FCoE enabled
so just force the code to always report FCoE is disabled, remove the
unused defines, and mark the OP as reserved.

Signed-off-by: Jesse Brandeburg <jesse.brandeburg@intel.com>
Tested-by: Andrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>