mlxsw: spectrum: Implement TC flower offload

Extend the existing setup_tc ndo call and allow to offload cls_flower
rules. Only limited set of dissector keys and actions are supported now.
Use previously introduced ACL infrastructure to offload cls_flower rules
to be processed in the HW.

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