mlxsw: spectrum: Offload multichain TC rules

Reflect chain index coming down from TC core and create a ruleset per
chain. Note that only chain 0, being the implicit chain, is bound to the
device for processing. The rest of chains have to be "jumped-to" by
actions.

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