ACPI: throttling: fix build warning

Signed-off-by: Len Brown <len.brown@intel.com>
diff --git a/drivers/acpi/processor_throttling.c b/drivers/acpi/processor_throttling.c
index 86c790e..1b8e592 100644
--- a/drivers/acpi/processor_throttling.c
+++ b/drivers/acpi/processor_throttling.c
@@ -987,7 +987,7 @@
 int acpi_processor_set_throttling(struct acpi_processor *pr, int state)
 {
 	cpumask_t saved_mask;
-	int ret;
+	int ret = 0;
 	unsigned int i;
 	struct acpi_processor *match_pr;
 	struct acpi_processor_throttling *p_throttling;