nfp: flower: update flow merge code to support IPv6 tunnels

Both pre-tunnel match rules and flow merge functions parse compiled
match/action fields for validation.

Update these validation functions to include IPv6 match and action fields.

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