tg3: APE heartbeat changes

tg3: APE heartbeat changes

In ungraceful host shutdown or driver crash case BMC connectivity is
lost. APE firmware is missing the driver state in this
case to keep the BMC connectivity alive.
This patch has below change to address this issue.

Heartbeat mechanism with APE firmware. This heartbeat mechanism
is needed to notify the APE firmware about driver state.

This patch also has the change in wait time for APE event from
1ms to 20ms as there can be some delay in getting response.

v2: Drop inline keyword as per David suggestion.

Signed-off-by: Prashant Sreedharan <prashant.sreedharan@broadcom.com>
Signed-off-by: Satish Baddipadige <satish.baddipadige@broadcom.com>
Signed-off-by: Siva Reddy Kallam <siva.kallam@broadcom.com>
Acked-by: Michael Chan <michael.chan@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>