mlxsw: spectrum_trap: Add ACL devlink-trap support

Add the trap group used to report ACL drops. Setup the trap IDs for
ingress/egress flow action drop. Register the two packet traps
associated with ACL trap group with devlink during driver
initialization. As these are "source traps", set the disabled
trap group to be the dummy, discarding as many packets in HW
as possible.

Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>