i40e: disable TPH

TPH is not currently enabled in this product, make sure it
isn't enabled by default.

Change-ID: Ibb1a10799c33c4c76dec06fcd53b1d6efa13c1f5
Signed-off-by: Jesse Brandeburg <jesse.brandeburg@intel.com>
Tested-by: Jim Young <jamesx.m.young@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>