3c59x: shorten timer period for slave devices

Jean Delvare reported bonding on top of 3c59x adapters was not detecting
network cable removal fast enough.

3c59x indeed uses a 60 seconds timer to check link status if carrier is
on, and 5 seconds if carrier is off.

This patch reduces timer period to 5 seconds if device is a bonding
slave.
Reported-by: NJean Delvare <jdelvare@suse.de>
Acked-by: NJean Delvare <jdelvare@suse.de>
Acked-by: NSteffen Klassert <steffen.klassert@secunet.com>
Signed-off-by: NEric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/ethernet/3com/3c59x.c

@@ -1842,7 +1842,7 @@ vortex_timer(unsigned long data)
 		ok = 1;
 	}
 
-	if (!netif_carrier_ok(dev))
+	if (dev->flags & IFF_SLAVE || !netif_carrier_ok(dev))
 		next_tick = 5*HZ;
 
 	if (vp->medialock)