bnxt_en: consolidate fw devlink health reporters

Merge 'fw' and 'fw_fatal' health reporters.  There is no longer a need
to distinguish between firmware reporters. Only bonafide errors are
reported now and no reports were being generated for the 'fw' reporter.

Signed-off-by: Edwin Peer <edwin.peer@broadcom.com>
Signed-off-by: Michael Chan <michael.chan@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>