mlxsw: spectrum: Implement action to set FID

Implement part of multipurpose Virtual Router and Forwarding Domain
Action that takes care of setting up FID. We need to use it to be able
to forward packets using ACL action when no FID is associated on RX.

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