nfp: dumpspec TLV traversal

- Perform dumpspec traversals for calculating size and populating the
  dump.
- Initially, wrap all spec TLVs in dump error TLVs (changed by later
  patches in the series).

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>