cpumask: alloc zeroed cpumask for static cpumask_var_ts

These are defined as static cpumask_var_t so if MAXSMP is not used,
they are cleared already.  Avoid surprises when MAXSMP is enabled.

Signed-off-by: Yinghai Lu <yinghai.lu@kernel.org>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
diff --git a/kernel/sched_rt.c b/kernel/sched_rt.c
index f2c66f8..9bf0d2a 100644
--- a/kernel/sched_rt.c
+++ b/kernel/sched_rt.c
@@ -1591,7 +1591,7 @@
 	unsigned int i;
 
 	for_each_possible_cpu(i)
-		alloc_cpumask_var_node(&per_cpu(local_cpu_mask, i),
+		zalloc_cpumask_var_node(&per_cpu(local_cpu_mask, i),
 					GFP_KERNEL, cpu_to_node(i));
 }
 #endif /* CONFIG_SMP */