nfp: bpf: add packet marking support

Add missing ABI defines and eBPF instructions to allow
mark to be passed on and extend prepend parsing on the
RX path to pick it up from packet metadata.

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