bnxt_en: Remove unnecessary NULL checks for fw_health

After fixing the allocation of bp->fw_health in the previous patch,
the driver will not go through the fw reset and recovery code paths
if bp->fw_health allocation fails.  So we can now remove the
unnecessary NULL checks.

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>