rcu: Fix coccinelle warnings

This commit fixes the following coccinelle warning:

kernel/rcu/tree.c:712:9-10: WARNING: return of 0/1 in function
'rcu_lockdep_current_cpu_online' with return type bool

Return statements in functions returning bool should use
 true/false instead of 1/0.
 Generated by: coccinelle/misc/boolreturn.cocci

Signed-off-by: Fengguang Wu <fengguang.wu@intel.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>

kernel/rcu/tree.c

@@ -725,7 +725,7 @@ bool rcu_lockdep_current_cpu_online(void)
 	bool ret;
 
 	if (in_nmi())
-		return 1;
+		return true;
 	preempt_disable();
 	rdp = this_cpu_ptr(&rcu_sched_data);
 	rnp = rdp->mynode;