bnxt_en: Improve wait for firmware commands completion

In situations where FW has crashed, the bnxt_hwrm_do_send_msg() call
will have to wait until timeout for each firmware message.  This
generally takes about half a second for each firmware message.  If we
try to unload the driver n this state, the unload sequence will take
a long time to complete.

Improve this by checking the health register if it is available and
abort the wait for the firmware response if the register shows that
firmware is not healthy.  The very first message HWRM_VER_GET is
excluded from this check because that message is used to poll for
firmware to come out of reset during error recovery.

Signed-off-by: Pavan Chebbi <pavan.chebbi@broadcom.com>
Signed-off-by: Michael Chan <michael.chan@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>