dock: bay: Don't call acpi_walk_namespace() when ACPI is disabled.

Signed-off-by: Len Brown <len.brown@intel.com>
diff --git a/drivers/acpi/dock.c b/drivers/acpi/dock.c
index 96c542f..bb7c51f 100644
--- a/drivers/acpi/dock.c
+++ b/drivers/acpi/dock.c
@@ -917,6 +917,9 @@
 
 	dock_station = NULL;
 
+	if (acpi_disabled)
+		return 0;
+
 	/* look for a dock station */
 	acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT,
 			    ACPI_UINT32_MAX, find_dock, &num, NULL);