doc: create an index for PDF files

Most of the content in the default index is HTML only, so create an
index just for PDF and keep it clean.

Signed-off-by: Anas Nashif <anas.nashif@intel.com>
diff --git a/doc/conf.py b/doc/conf.py
index c8c6169..13218e3 100644
--- a/doc/conf.py
+++ b/doc/conf.py
@@ -158,7 +158,7 @@
 }
 
 latex_documents = [
-    ("index", "zephyr.tex", "Zephyr Project Documentation", "many", "manual"),
+    ("index-tex", "zephyr.tex", "Zephyr Project Documentation", "many", "manual"),
 ]
 
 # -- Options for zephyr.doxyrunner plugin ---------------------------------
diff --git a/doc/index-tex.rst b/doc/index-tex.rst
new file mode 100644
index 0000000..19fed0d
--- /dev/null
+++ b/doc/index-tex.rst
@@ -0,0 +1,24 @@
+:orphan:
+
+..
+    Zephyr Project documentation main file
+
+.. _zephyr-home-tex:
+
+Zephyr Project Documentation
+############################
+
+
+.. toctree::
+   :maxdepth: 1
+   :caption: Contents
+
+   introduction/index.rst
+   getting_started/index.rst
+   contribute/index.rst
+   development_process/index.rst
+   guides/build/index.rst
+   application/index.rst
+   reference/index.rst
+   guides/index.rst
+   security/index.rst
diff --git a/doc/index.rst b/doc/index.rst
index bebc25b..2046f60 100644
--- a/doc/index.rst
+++ b/doc/index.rst
@@ -18,18 +18,16 @@
    **Welcome to the Zephyr Project's documentation
    for the main tree under development** (version |version|).
 
-.. only:: html
+Use the version selection menu on the left to view
+documentation for a specific version of Zephyr.
 
-   Use the version selection menu on the left to view
-   documentation for a specific version of Zephyr.
+For information about the changes and additions for releases, please
+consult the published :ref:`zephyr_release_notes` documentation.
 
-   For information about the changes and additions for releases, please
-   consult the published :ref:`zephyr_release_notes` documentation.
-
-   The Zephyr OS is provided under the `Apache 2.0 license`_ (as found in
-   the LICENSE file in the project's `GitHub repo`_).  The Zephyr OS also
-   imports or reuses packages, scripts, and other files that use other
-   licensing, as described in :ref:`Zephyr_Licensing`.
+The Zephyr OS is provided under the `Apache 2.0 license`_ (as found in
+the LICENSE file in the project's `GitHub repo`_).  The Zephyr OS also
+imports or reuses packages, scripts, and other files that use other
+licensing, as described in :ref:`Zephyr_Licensing`.
 
 
 .. raw:: html
@@ -96,10 +94,8 @@
        </li>
    </ul>
 
-.. only:: html
-
-   Sections
-   ********
+Sections
+********
 
 .. toctree::
    :maxdepth: 1
@@ -118,16 +114,12 @@
    boards/index.rst
    releases/index.rst
 
-.. only:: html
+Indices and Tables
+******************
 
-   Indices and Tables
-   ******************
-
-.. only:: html
-
-   * :ref:`configuration_options`
-   * :ref:`glossary`
-   * :ref:`genindex`
+* :ref:`configuration_options`
+* :ref:`glossary`
+* :ref:`genindex`
 
 .. _Apache 2.0 license:
    https://github.com/zephyrproject-rtos/zephyr/blob/main/LICENSE