wcte12xp: Close a potential race on driver unload.

The shutdown logic requires that all CPUs see that the INITIALIZED bit
has been cleared. Otherwise it may be possible for the workqueue to run
after the hardware resources have been released.

Signed-off-by: Shaun Ruffell <sruffell@digium.com>
Acked-by: Russ Meyerriecks <rmeyerriecks@digium.com>

Origin: http://svnview.digium.com/svn/dahdi?view=rev&rev=10047

git-svn-id: http://svn.asterisk.org/svn/dahdi/linux/branches/2.4@10049 a0bf4364-ded3-4de4-8d8a-66a801d63aff

drivers/dahdi/wcte12xp/base.c

@@ -2381,6 +2381,7 @@ static void __devexit te12xp_remove_one(struct pci_dev *pdev)
 	remove_sysfs_files(wc);
 
 	clear_bit(INITIALIZED, &wc->bit_flags);
+	smp_mb__after_clear_bit();
 
 	del_timer_sync(&wc->timer);
 	flush_workqueue(wc->wq);