yam: replace del_timer by del_timer_sync

Use del_timer_sync to ensure that the timer is stopped on all CPUs before
the driver exists.

This change was suggested by Thomas Gleixner

The semantic patch that makes this change is as follows:
(http://coccinelle.lip6.fr/)

// <smpl>
@r@
declarer name module_exit;
identifier ex;
@@

module_exit(ex);

@@
identifier r.ex;
@@

ex(...) {
  <...
- del_timer
+ del_timer_sync
    (...)
  ...>
}
// </smpl>
Signed-off-by: NJulia Lawall <Julia.Lawall@lip6.fr>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/hamradio/yam.c

@@ -1184,7 +1184,7 @@ static void __exit yam_cleanup_driver(void)
 	struct yam_mcs *p;
 	int i;
 
-	del_timer(&yam_timer);
+	del_timer_sync(&yam_timer);
 	for (i = 0; i < NR_PORTS; i++) {
 		struct net_device *dev = yam_devs[i];
 		if (dev) {