Revert "GCC: Upgrade to version 9.2-2019.12 of toolchain" ...

This reverts commit de9bf1d.

Change-Id: Iebb6297ce290a10ee850bf6a9c71e7eb530b085f

GCC: Upgrade to version 9.2-2019.12 of toolchain ...

This toolchain provides multiple cross compilers and are publicly
available on www.developer.arm.com

We thoroughly test TF-A in CI using:
AArch32 bare-metal target (arm-none-eabi)
AArch64 ELF bare-metal target (aarch64-none-elf)

Change-Id: I2360a3ac6705c68dca781b85e9894867df255b3e
Signed-off-by: Madhukar Pappireddy <madhukar.pappireddy@arm.com>

doc: Fix platform port inclusion ...

This patch:

- Adds any leftover platform ports that were not having their
  documentation built (not in the index.rst table of contents)
- Corrects a handful of RST formatting errors that cause poor
  rendering
- Reorders the list of platforms so that they are displayed
  in alphabetical order

Change-Id: If8c135a822d581c3c5c4fca2936d501ccfd2e94c
Signed-off-by: Paul Beesley <paul.beesley@arm.com>

doc: Reformat platform port documents ...

The platform port documents are not very standardised right now and
they don't integrate properly into the document tree so:

1) Make sure each port has a proper name and title (incl. owner)
2) Correct use of headings, subheadings, etc in each port
3) Resolve any naming conflicts between documents

Change-Id: I4c2da6f57172b7f2af3512e766ae9ce3b840b50f
Signed-off-by: Paul Beesley <paul.beesley@arm.com>

plat: intel: Add BL31 support to Intel Stratix10 SoCFPGA platform ...

This adds BL31 support to Intel Stratix10 SoCFPGA platform. BL31 in TF-A
supports:
- PSCI calls to enable 4 CPU cores
- PSCI mailbox calls for FPGA reconfiguration

Signed-off-by: Loh Tien Hock <tien.hock.loh@intel.com>