rcu: Use bool type for return value in rcu_is_watching()

Use a bool type for return in rcu_is_watching().
Signed-off-by: NPranith Kumar <bobby.prani@gmail.com>
Signed-off-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>

kernel/rcu/tree.c

@@ -819,7 +819,7 @@ bool notrace __rcu_is_watching(void)
  */
 bool notrace rcu_is_watching(void)
 {
-	int ret;
+	bool ret;
 
 	preempt_disable();
 	ret = __rcu_is_watching();