rcu_dereference_raw() calls indirectly rcu_read_lock_held() while
rcu_dereference_raw_notrace() does not so fix the comment about the latter.
Signed-off-by: NAlexey Kardashevskiy <aik@ozlabs.ru>
Signed-off-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>