Input: create a book with Linux Input documentation

Now that all files under Documentation/input follows the ReST markup
language, rename them to *.rst and create a book for the Linux Input
subsystem.

Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

Documentation/input/conf.py

@@ -0,0 +1,10 @@
+# -*- coding: utf-8; mode: python -*-
+
+project = "The Linux input driver subsystem"
+
+tags.add("subproject")
+
+latex_documents = [
+    ('index', 'linux-input.tex', project,
+     'The kernel development community', 'manual'),
+]