[Feature]add MT2731_MP2_MR2_SVN388 baseline version

Change-Id: Ief04314834b31e27effab435d3ca8ba33b499059
diff --git a/src/kernel/linux/v4.14/Documentation/sound/index.rst b/src/kernel/linux/v4.14/Documentation/sound/index.rst
new file mode 100644
index 0000000..47b89f0
--- /dev/null
+++ b/src/kernel/linux/v4.14/Documentation/sound/index.rst
@@ -0,0 +1,20 @@
+===================================
+Linux Sound Subsystem Documentation
+===================================
+
+.. toctree::
+   :maxdepth: 2
+
+   kernel-api/index
+   designs/index
+   soc/index
+   alsa-configuration
+   hd-audio/index
+   cards/index
+
+.. only::  subproject
+
+   Indices
+   =======
+
+   * :ref:`genindex`