rcu: Fix incorrect notes for code

Signed-off-by: NLiu Ping Fan <kernelfans@gmail.com>
Signed-off-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: NJosh Triplett <josh@joshtriplett.org>

kernel/rcu/tree_plugin.h

@@ -2109,7 +2109,7 @@ static void rcu_init_one_nocb(struct rcu_node *rnp)
 }
 
 #ifndef CONFIG_RCU_NOCB_CPU_ALL
-/* Is the specified CPU a no-CPUs CPU? */
+/* Is the specified CPU a no-CBs CPU? */
 bool rcu_is_nocb_cpu(int cpu)
 {
 	if (have_rcu_nocb_mask)