nfp: add support for indirect HWinfo lookup

Management FW can adjust some of the information in the HWinfo table
at runtime.  In some cases reading the table directly will not yield
correct results.  Add a NSP command for looking up information.
Up until now we weren't making use of any of the values which may
get adjusted.

Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: Dirk van der Merwe <dirk.vandermerwe@netronome.com>
Signed-off-by: David S. Miller <davem@davemloft.net>