bnxt_en: Add new FW devlink_health_reporter

Create new FW devlink_health_reporter, to know the current health
status of FW.

Command example and output:
$ devlink health show pci/0000:af:00.0 reporter fw

pci/0000:af:00.0:
  name fw
    state healthy error 0 recover 0

 FW status: Healthy; Reset count: 1

Cc: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: Vasundhara Volam <vasundhara-v.volam@broadcom.com>
Signed-off-by: Michael Chan <michael.chan@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>