ACPICA: Additional error checking for pathname utilities

Add error check after all calls to acpi_ns_get_pathname_length.
Add status return from acpi_ns_build_external_path and check after
all calls.  Add parameter validation to acpi_ut_initialize_buffer.

Reported by and initial patch by Ingo Molnar.
http://lkml.org/lkml/2008/7/21/176

Signed-off-by: Bob Moore <robert.moore@intel.com>
Signed-off-by: Lin Ming <ming.m.lin@intel.com>
Signed-off-by: Andi Kleen <ak@linux.intel.com>
diff --git a/include/acpi/acnamesp.h b/include/acpi/acnamesp.h
index 9ed70a0..c340085 100644
--- a/include/acpi/acnamesp.h
+++ b/include/acpi/acnamesp.h
@@ -182,7 +182,7 @@
  */
 u32 acpi_ns_opens_scope(acpi_object_type type);
 
-void
+acpi_status
 acpi_ns_build_external_path(struct acpi_namespace_node *node,
 			    acpi_size size, char *name_buffer);