bnxt_en: Invalidate health register mapping at the end of probe.

After probe is successful, interface may not be bought up in all
the cases and health register mapping could be invalid if firmware
undergoes reset. Fix it by invalidating the health register at the
end of probe. It will be remapped during ifup.

Fixes: 43a440c4

 ("bnxt_en: Improve the status_reliable flag in bp->fw_health.")
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>