i40e: remove i40e_fcoe files

i40e_fcoe support was removed via commit 9eed69a9 ("i40e: Drop FCoE code from core driver files")
But this left files in place but un-compilable.
Let's finish the cleaning.

Signed-off-by: Corentin Labbe <clabbe@baylibre.com>
Tested-by: Andrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>