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/arch/x86/kernel/cpu/cpufreq/powernow-k7.c b/arch/x86/kernel/cpu/cpufreq/powernow-k7.c
index a8363e5..d47c775 100644
--- a/arch/x86/kernel/cpu/cpufreq/powernow-k7.c
+++ b/arch/x86/kernel/cpu/cpufreq/powernow-k7.c
@@ -322,7 +322,7 @@
 		goto err0;
 	}
 
-	if (!alloc_cpumask_var(&acpi_processor_perf->shared_cpu_map,
+	if (!zalloc_cpumask_var(&acpi_processor_perf->shared_cpu_map,
 								GFP_KERNEL)) {
 		retval = -ENOMEM;
 		goto err05;