PM / Wakeup: Remove useless synchronize_rcu() call

wakeup_source_add() adds an item into wakeup_sources list.

There is no need to call synchronize_rcu() at this point.

Its only needed in wakeup_source_remove()
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>

drivers/base/power/wakeup.c

@@ -110,7 +110,6 @@ void wakeup_source_add(struct wakeup_source *ws)
 	spin_lock_irq(&events_lock);
 	list_add_rcu(&ws->entry, &wakeup_sources);
 	spin_unlock_irq(&events_lock);
-	synchronize_rcu();
 }
 EXPORT_SYMBOL_GPL(wakeup_source_add);