treewide: fix synchronize_rcu() in comments

Signed-off-by: NJesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: NJiri Kosina <jkosina@suse.cz>

include/linux/percpu-refcount.h

@@ -29,7 +29,7 @@
  * calls io_destroy() or the process exits.
  *
  * In the aio code, kill_ioctx() is called when we wish to destroy a kioctx; it
- * calls percpu_ref_kill(), then hlist_del_rcu() and sychronize_rcu() to remove
+ * calls percpu_ref_kill(), then hlist_del_rcu() and synchronize_rcu() to remove
  * the kioctx from the proccess's list of kioctxs - after that, there can't be
  * any new users of the kioctx (from lookup_ioctx()) and it's then safe to drop
  * the initial ref with percpu_ref_put().

net/rds/af_rds.c

@@ -83,7 +83,7 @@ static int rds_release(struct socket *sock)
 
 	/*
 	 * the binding lookup hash uses rcu, we need to
-	 * make sure we sychronize_rcu before we free our
+	 * make sure we synchronize_rcu before we free our
 	 * entry
 	 */
 	rds_remove_bound(rs);