This adds both the source and destination chain id to the information kept
for enabled port lookups.
This allows enabling and disabling a chain of lookups by walking the chain
information for a port.

This changes the way that VCAP lookups are enabled from userspace: instead
of one matchall rule that enables all the 4 Sparx5 IS2 lookups, you need a
matchall rule per lookup.

In practice that is done by adding one matchall rule in chain 0 to goto IS2
Lookup 0, and then for each lookup you add a rule per lookup (low priority)
that does a goto to the next lookup chain.

Examples:

If you want IS2 Lookup 0 to be enabled you add the same matchall filter as
before:

tc filter add dev eth12 ingress chain 0 prio 1000 handle 1000 matchall \
       skip_sw action goto chain 8000000

If you also want to enable lookup 1 to 3 in IS2 and chain them you need
to add the following matchall filters:

tc filter add dev eth12 ingress chain 8000000 prio 1000 handle 1000 \
    matchall skip_sw action goto chain 8100000

tc filter add dev eth12 ingress chain 8100000 prio 1000 handle 1000 \
    matchall skip_sw action goto chain 8200000

tc filter add dev eth12 ingress chain 8200000 prio 1000 handle 1000 \
    matchall skip_sw action goto chain 8300000
Signed-off-by: Horatiu Vultur <horatiu.vultur@microchip.com>
Signed-off-by: Steen Hegelund <steen.hegelund@microchip.com>
Signed-off-by: David S. Miller <davem@davemloft.net>