net: ethernet: aquantia: Handle error cleanup of start on open

The aq_nic_start function can fail in a variety of cases which leaves
the device in broken state.

An example case where the start function fails is the
request_threaded_irq which can be interrupted, resulting in a EINTR
result. This can be manually triggered by bringing the link up (e.g. ip
link set up) and triggering a SIGINT on the initiating process (e.g.
Ctrl+C). This would put the device into a half configured state.
Subsequently bringing the link up again would cause the napi_enable to
BUG.

In order to correctly clean up the failed attempt to start a device call
aq_nic_stop.
Signed-off-by: Nathan Rossi <nathan.rossi@digi.com>
Reviewed-by: Igor Russkikh <irusskikh@marvell.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/aquantia/atlantic/aq_main.c

@@ -71,8 +71,10 @@ static int aq_ndev_open(struct net_device *ndev)
 		goto err_exit;
 
 	err = aq_nic_start(aq_nic);
-	if (err < 0)
+	if (err < 0) {
+		aq_nic_stop(aq_nic);
 		goto err_exit;
+	}
 
 err_exit:
 	if (err < 0)