ACPICA: Add Buffer->String conversion for predefined methods

For predefined methods (such as _BIF), add automatic conversion for
objects that are required to be a String, but a Buffer was found
instead. This can happen when reading string battery data from
an operation region, because it used to be difficult to convert
the data from buffer to string from within the ASL. Linux BZ 11822.

http://bugzilla.kernel.org/show_bug.cgi?id=11822Signed-off-by: Bob Moore <robert.moore@intel.com>
Signed-off-by: Lin Ming <ming.m.lin@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>

drivers/acpi/namespace/nseval.c

@@ -282,8 +282,7 @@ acpi_status acpi_ns_evaluate(struct acpi_evaluate_info * info)
 			 * the method on invalid return object.
 			 */
 			(void)acpi_ns_check_predefined_names(node,
-							     info->
-							     return_object);
+			     &info->return_object);
 		}
 
 		/* Mark the node as having been evaluated */

include/acpi/acnamesp.h

@@ -182,7 +182,7 @@ acpi_status acpi_ns_evaluate(struct acpi_evaluate_info *info);
  */
 acpi_status
 acpi_ns_check_predefined_names(struct acpi_namespace_node *node,
-			       union acpi_operand_object *return_object);
+			       union acpi_operand_object **return_object);
 
 const union acpi_predefined_info *acpi_ns_check_for_predefined_name(struct
 								    acpi_namespace_node