parport: make lockdep happy with waitlist_lock

parport_unregister_device() should never be used when interrupts are
enabled in hardware and irq handler is registered so there is no need to
disable interrupts when using waitlist_lock.  But there is no way to
explain this subtle semantics to lockdep analyzer.

So disable interrupts here too to simplify things.  The price is
negligible.

Signed-off-by: Alexander Gordeev <lasaine@lvk.cs.msu.su>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

drivers/parport/share.c

@@ -678,7 +678,7 @@ void parport_unregister_device(struct pardevice *dev)
 
 	/* Make sure we haven't left any pointers around in the wait
 	 * list. */
-	spin_lock (&port->waitlist_lock);
+	spin_lock_irq(&port->waitlist_lock);
 	if (dev->waitprev || dev->waitnext || port->waithead == dev) {
 		if (dev->waitprev)
 			dev->waitprev->waitnext = dev->waitnext;
@@ -689,7 +689,7 @@ void parport_unregister_device(struct pardevice *dev)
 		else
 			port->waittail = dev->waitprev;
 	}
-	spin_unlock (&port->waitlist_lock);
+	spin_unlock_irq(&port->waitlist_lock);
 
 	kfree(dev->state);
 	kfree(dev);