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/acpi/processor_core.c b/drivers/acpi/processor_core.c
index 45ad328..23f0fb8 100644
--- a/drivers/acpi/processor_core.c
+++ b/drivers/acpi/processor_core.c
@@ -844,7 +844,7 @@
 	if (!pr)
 		return -ENOMEM;
 
-	if (!alloc_cpumask_var(&pr->throttling.shared_cpu_map, GFP_KERNEL)) {
+	if (!zalloc_cpumask_var(&pr->throttling.shared_cpu_map, GFP_KERNEL)) {
 		kfree(pr);
 		return -ENOMEM;
 	}