firewire: fix unloading of fw-ohci while devices are attached

Fix panic in run_timer_softirq right after "modprobe -r firewire-ohci"
if a FireWire disk was attached and firewire-sbp2 loaded.

Signed-off-by: Stefan Richter <[e-mail]>

drivers/firewire/fw-card.c

···
 	/* Set up the dummy driver. */
 	card->driver = &dummy_driver;
 
-	fw_flush_transactions(card);
-
 	fw_destroy_nodes(card);
+	flush_scheduled_work();
+
+	fw_flush_transactions(card);
+	del_timer_sync(&card->flush_timer);
 
 	fw_card_put(card);
 }