nfp: flower: compile Geneve match fields

Compile Geneve match fields for offloading to the NFP. The addition of
Geneve overflows the 8 bit key_layer field, so apply extended metadata to
the match cmsg allowing up to 32 more key_layer fields.

Rather than adding new Geneve blocks, move the vxlan code to generic ipv4
udp tunnel structs and use these for both vxlan and Geneve.

Matches are only supported when specifically mentioning well known port
6081. Geneve tunnel options are not yet included in the match.

Only offload Geneve if the fw supports it - include check for this.

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