ACPICA: Add post-order callback to acpi_walk_namespace

The existing interface only has a pre-order callback. This change
adds an additional parameter for a post-order callback which will
be more useful for bus scans. ACPICA BZ 779.

Also update the external calls to acpi_walk_namespace.

http://www.acpica.org/bugzilla/show_bug.cgi?id=779

Signed-off-by: Lin Ming <ming.m.lin@intel.com>
Signed-off-by: Bob Moore <robert.moore@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>

drivers/acpi/scan.c

@@ -1332,7 +1332,7 @@ static int acpi_bus_scan(acpi_handle handle, struct acpi_bus_ops *ops,
 	status = acpi_bus_check_add(handle, 0, ops, &device);
 	if (ACPI_SUCCESS(status))
 		acpi_walk_namespace(ACPI_TYPE_ANY, handle, ACPI_UINT32_MAX,
-				    acpi_bus_check_add, ops, &device);
+				    acpi_bus_check_add, NULL, ops, &device);
 
 	if (child)
 		*child = device;