i40e: fix PTP bug

The receive hang detection routine was never being run when
PTP was enabled.

Change-ID: I200f35b0f3190d31b595df89d678f4c8a2131ba0
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>