nfp: bpf: prepare for parsing BPF FW capabilities

BPF FW creates a run time symbol called bpf_capabilities which
contains TLV-formatted capability information.  Allocate app
private structure to store parsed capabilities and add a skeleton
of parsing logic.

Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>