Add packet trap that can report packets that reached the router, but are
non-routable. For example, IGMP queries can be flooded by the device in
layer 2 and reach the router. Such packets should not be routed and
instead dropped.

Signed-off-by: Amit Cohen <amitc@mellanox.com>
Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>