docs: Fixes and updates for the v2.3 release ...

A small set of misc changes to ensure correctness before the v2.3
release.

Signed-off-by: Lauren Wehrmeister <lauren.wehrmeister@arm.com>
Change-Id: I5b4e35b3b46616df0453cecff61f5a414951cd62

rpi: docs: Update maintainers file to new RPi directory scheme ...

With the addition of the Raspberry Pi 4 port the directory structure
changed a bit, also the new port didn't have a separate entry.

Add a new entry for the RPi4 port and adjust the path names.

Signed-off-by: Andre Przywara <andre.przywara@arm.com>
Change-Id: I04b60e729a19bb0cc3dd6ce6899ec6480356b1f1

Update pathnames in maintainers.rst file ...

The maintainers.rst file lists files and directories that each contributor looks
after in the TF-A source tree. As files and directories move around over time,
some pathnames had become invalid. Fix them, either by updating the path if
it has just moved, or deleting it altogether if it doesn't seem to exist
anymore.

Change-Id: Idb6ff4d8d0b593138d4f555ec206abcf68b0064f
Signed-off-by: Sandrine Bailleux <sandrine.bailleux@arm.com>

amlogic: axg: Add support for the A113D (AXG) platform ...

Introduce the preliminary support for the Amlogic A113D (AXG) SoC.

This port is a minimal implementation of BL31 capable of booting
mainline U-Boot, Linux and chainloading BL32 (ATOS).

Tested on a A113D board.

Signed-off-by: Carlo Caione <ccaione@baylibre.com>
Change-Id: Ic4548fa2f7c48d61b485b2a6517ec36c53c20809

Update list of main maintainers ...

Change-Id: Ia4faf873f8946992737f76870ac92bc5cb3f4020
Signed-off-by: Sandrine Bailleux <sandrine.bailleux@arm.com>

doc: Final, pre-release fixes and updates ...

A small set of misc changes to ensure correctness before the v2.2
release tagging.

Change-Id: I888840b9483ea1a1633d204fbbc0f9594072101e
Signed-off-by: Paul Beesley <paul.beesley@arm.com>

doc: Move "About" content from index.rst to a new chapter ...

The index.rst page is now the primary landing page for the TF-A
documentation. It contains quite a lot of content these days,
including:

- The project purpose and general intro
- A list of functionality
- A list of planned functionality
- A list of supported platforms
- "Getting started" links to other documents
- Contact information for raising issues

This patch creates an "About" chapter in the table
of contents and moves some content there. In order,
the above listed content:

- Stayed where it is. This is the right place for it.
- Moved to About->Features
- Moved to About->Features (in subsection)
- Stayed where it is. Moved in a later patch.
- Was expanded in-place
- Moved to About->Contact

Change-Id: I254bb87560fd09140b9e485cf15246892aa45943
Signed-off-by: Paul Beesley <paul.beesley@arm.com>