docs(porting): move porting guide upper in table of contents

The porting guide is currently hosted under the 'Getting started'
section. Yet, porting the full firmware to a new platform is probably
not the first thing that one would do. Before delving into the
details, one would probably start by building the code for an emulated
platform, such as Arm FVP.

Furthermore, the porting guide is such a big and important document
that it probably deserves being visible in the main table of contents.
Thus, move it just above the list of supported platforms.

Signed-off-by: Sandrine Bailleux <sandrine.bailleux@arm.com>
Change-Id: I51b3d2a93832505ab90d73c823f06f9540e84c77
diff --git a/docs/getting_started/index.rst b/docs/getting_started/index.rst
index 5ebabea..8180a3f 100644
--- a/docs/getting_started/index.rst
+++ b/docs/getting_started/index.rst
@@ -12,10 +12,9 @@
    build-options
    build-internals
    image-terminology
-   porting-guide
    psci-lib-integration-guide
    rt-svc-writers-guide
 
 --------------
 
-*Copyright (c) 2019, Arm Limited. All rights reserved.*
+*Copyright (c) 2019-2023, Arm Limited. All rights reserved.*
diff --git a/docs/index.rst b/docs/index.rst
index 3860199..d5ab8fc 100644
--- a/docs/index.rst
+++ b/docs/index.rst
@@ -11,6 +11,7 @@
    process/index
    components/index
    design/index
+   porting-guide
    plat/index
    perf/index
    security_advisories/index
@@ -84,7 +85,7 @@
 
 --------------
 
-*Copyright (c) 2013-2021, Arm Limited and Contributors. All rights reserved.*
+*Copyright (c) 2013-2023, Arm Limited and Contributors. All rights reserved.*
 
 .. _Armv7-A and Armv8-A: https://developer.arm.com/products/architecture/a-profile
 .. _Secure Monitor: http://www.arm.com/products/processors/technologies/trustzone/tee-smc.php
diff --git a/docs/getting_started/porting-guide.rst b/docs/porting-guide.rst
similarity index 99%
rename from docs/getting_started/porting-guide.rst
rename to docs/porting-guide.rst
index 21e0289..366734c 100644
--- a/docs/getting_started/porting-guide.rst
+++ b/docs/porting-guide.rst
@@ -3578,7 +3578,7 @@
 storage access is only required by BL1 and BL2 phases and performed inside the
 ``load_image()`` function in ``bl_common.c``.
 
-.. uml:: ../resources/diagrams/plantuml/io_framework_usage_overview.puml
+.. uml:: resources/diagrams/plantuml/io_framework_usage_overview.puml
 
 It is mandatory to implement at least one storage driver. For the Arm
 development platforms the Firmware Image Package (FIP) driver is provided as
@@ -3588,7 +3588,7 @@
 in ``drivers/io/io_storage.c`` and the driver files are located in
 ``drivers/io/``.
 
-.. uml:: ../resources/diagrams/plantuml/io_arm_class_diagram.puml
+.. uml:: resources/diagrams/plantuml/io_arm_class_diagram.puml
 
 Each IO driver must provide ``io_dev_*`` structures, as described in
 ``drivers/io/io_driver.h``. These are returned via a mandatory registration
@@ -3599,12 +3599,12 @@
 abstraction layer. These drivers then need to be initialized by bootloader
 phases as required in their respective ``blx_platform_setup()`` functions.
 
-.. uml:: ../resources/diagrams/plantuml/io_dev_registration.puml
+.. uml:: resources/diagrams/plantuml/io_dev_registration.puml
 
 The storage abstraction layer provides mechanisms (``io_dev_init()``) to
 initialize storage devices before IO operations are called.
 
-.. uml:: ../resources/diagrams/plantuml/io_dev_init_and_check.puml
+.. uml:: resources/diagrams/plantuml/io_dev_init_and_check.puml
 
 The basic operations supported by the layer
 include ``open()``, ``close()``, ``read()``, ``write()``, ``size()`` and ``seek()``.