i40e: Add functionality for FD SB to drop packets

With this change we can drop a flow if we wanted to.

Change-ID: I222b1ae960e61a31965bafe3159a95099e70c7d2
Signed-off-by: Anjali Singhai Jain <anjali.singhai@intel.com>
Signed-off-by: Catherine Sullivan <catherine.sullivan@intel.com>
Tested-by: Kavindya Deegala <kavindya.s.deegala@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>