nfp: report NSP ABI version in ethtool FW version

ethtool_drvinfo->fw_version can cantain multiple FW strings.
We already report NFD ABI version there, add NSP ABI version
if available (i.e. on PF) with 'sp:' prefix.

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