[ACPI] add static to function definitions

Signed-off-by: Adrian Bunk <bunk@stusta.de>
Signed-off-by: Len Brown <len.brown@intel.com>
diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c
index 8a3ea41..c6db591 100644
--- a/drivers/acpi/scan.c
+++ b/drivers/acpi/scan.c
@@ -527,7 +527,7 @@
 	return_VALUE(0);
 }
 
-int acpi_start_single_object(struct acpi_device *device)
+static int acpi_start_single_object(struct acpi_device *device)
 {
 	int result = 0;
 	struct acpi_driver *driver;