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/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c
index 47d2ad0..6e2ec0b 100644
--- a/drivers/cpufreq/cpufreq.c
+++ b/drivers/cpufreq/cpufreq.c
@@ -808,7 +808,7 @@
 		ret = -ENOMEM;
 		goto nomem_out;
 	}
-	if (!alloc_cpumask_var(&policy->related_cpus, GFP_KERNEL)) {
+	if (!zalloc_cpumask_var(&policy->related_cpus, GFP_KERNEL)) {
 		free_cpumask_var(policy->cpus);
 		kfree(policy);
 		ret = -ENOMEM;