ACPI: acpi_pad: Fix memory leak in power saving threads

Fix once per second (round_robin_time) memory leak of about 1 KB in
each acpi_pad kernel idling thread that is activated.

Found by testing with kmemleak.

Signed-off-by: Lenny Szubowicz <lszubowi@redhat.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

drivers/acpi/acpi_pad.c

@@ -110,6 +110,7 @@ static void round_robin_cpu(unsigned int tsk_index)
 		cpumask_andnot(tmp, cpu_online_mask, pad_busy_cpus);
 	if (cpumask_empty(tmp)) {
 		mutex_unlock(&round_robin_lock);
+		free_cpumask_var(tmp);
 		return;
 	}
 	for_each_cpu(cpu, tmp) {
@@ -127,6 +128,8 @@ static void round_robin_cpu(unsigned int tsk_index)
 	mutex_unlock(&round_robin_lock);
 
 	set_cpus_allowed_ptr(current, cpumask_of(preferred_cpu));
+
+	free_cpumask_var(tmp);
 }
 
 static void exit_round_robin(unsigned int tsk_index)