Documentation: ACPI: move dsd/data-node-references.txt to firmware-guide/acpi and convert to reST

This converts the plain text documentation to reStructuredText format
and adds it to Sphinx TOC tree.

No essential content change.

Signed-off-by: Changbin Du <changbin.du@gmail.com>
Reviewed-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

Documentation/firmware-guide/acpi/dsd/data-node-references.rst

@@ -1,9 +1,12 @@
-Copyright (C) 2018 Intel Corporation
-Author: Sakari Ailus <sakari.ailus@linux.intel.com>
-
+.. SPDX-License-Identifier: GPL-2.0
+.. include:: <isonum.txt>
 
+===================================
 Referencing hierarchical data nodes
------------------------------------
+===================================
+
+:Copyright: |copy| 2018 Intel Corporation
+:Author: Sakari Ailus <sakari.ailus@linux.intel.com>
 
 ACPI in general allows referring to device objects in the tree only.
 Hierarchical data extension nodes may not be referred to directly, hence this
@@ -28,13 +31,14 @@ extension key.
 
 
 Example
--------
+=======
 
-	In the ASL snippet below, the "reference" _DSD property [2] contains a
-	device object reference to DEV0 and under that device object, a
-	hierarchical data extension key "node@1" referring to the NOD1 object
-	and lastly, a hierarchical data extension key "anothernode" referring to
-	the ANOD object which is also the final target node of the reference.
+In the ASL snippet below, the "reference" _DSD property [2] contains a
+device object reference to DEV0 and under that device object, a
+hierarchical data extension key "node@1" referring to the NOD1 object
+and lastly, a hierarchical data extension key "anothernode" referring to
+the ANOD object which is also the final target node of the reference.
+::
 
 	Device (DEV0)
 	{
@@ -75,15 +79,15 @@ Example
 	    })
 	}
 
-Please also see a graph example in graph.txt .
+Please also see a graph example in :doc:`graph`.
 
 References
-----------
+==========
 
 [1] Hierarchical Data Extension UUID For _DSD.
-    <URL:http://www.uefi.org/sites/default/files/resources/_DSD-hierarchical-data-extension-UUID-v1.1.pdf>,
-    referenced 2018-07-17.
+<http://www.uefi.org/sites/default/files/resources/_DSD-hierarchical-data-extension-UUID-v1.1.pdf>,
+referenced 2018-07-17.
 
 [2] Device Properties UUID For _DSD.
-    <URL:http://www.uefi.org/sites/default/files/resources/_DSD-device-properties-UUID.pdf>,
-    referenced 2016-10-04.
+<http://www.uefi.org/sites/default/files/resources/_DSD-device-properties-UUID.pdf>,
+referenced 2016-10-04.

Documentation/firmware-guide/acpi/index.rst

@@ -9,6 +9,7 @@ ACPI Support
 
    namespace
    dsd/graph
+   dsd/data-node-references
    enumeration
    osi
    method-customizing