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>
diff --git a/drivers/pci/hotplug/acpi_pcihp.c b/drivers/pci/hotplug/acpi_pcihp.c
index a73028e..0f32571 100644
--- a/drivers/pci/hotplug/acpi_pcihp.c
+++ b/drivers/pci/hotplug/acpi_pcihp.c
@@ -471,7 +471,7 @@
 		return found;
 
 	acpi_walk_namespace(ACPI_TYPE_DEVICE, handle, 1,
-			    check_hotplug, (void *)&found, NULL);
+			    check_hotplug, NULL, (void *)&found, NULL);
 	return found;
 }
 EXPORT_SYMBOL_GPL(acpi_pci_detect_ejectable);