net: sched: include mpls actions in hardware intermediate representation

A recent addition to TC actions is the ability to manipulate the MPLS
headers on packets.

In preparation to offload such actions to hardware, update the IR code to
accept and prepare the new actions.

Note that no driver currently impliments the MPLS dec_ttl action so this
is not included.

Signed-off-by: John Hurley <john.hurley@netronome.com>
Reviewed-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: David S. Miller <davem@davemloft.net>