nfp: dump all hwinfo

- Dump hwinfo as separate TLV chunk, in a packed format containing
  zero-separated key and value strings.
- This provides additional debug context, if requested by the dumpspec.

Signed-off-by: Carl Heymann <carl.heymann@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>