allwinner: Add Allwinner H6 SoC support ...

The H6 is Allwinner's most recent SoC. It shares most peripherals with the
other ARMv8 Allwinner SoCs (A64/H5), but has a completely different memory
map.

Introduce a separate platform target, which includes a different header
file to cater for the address differences. Also add the new build target
to the documentation.

The new ATF platform name is "sun50i_h6".

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

allwinner: doc: add missing paragraphs ...

Add two empty lines to denote the paragraphs properly and improve
readability.

Reported-by: Samuel Holland <samuel@sholland.org>
Signed-off-by: Andre Przywara <andre.przywara@arm.com>

allwinner: Add BL32 (corresponds to Trusted OS) support ...

This patch is an attempt to run Trusted OS (OP-TEE OS being one of them) along
side BL31 image.

ATF supports multiple SPD's that can take dispatcher name (opteed for OP-TEE OS)
as an input using the 'SPD=<dispatcher name>' option during bl31 build.

Signed-off-by: Amit Singh Tomar <amittomer25@gmail.com>

allwinner: Add Allwinner A64 support ...

The Allwinner A64 SoC is quite popular on single board computers.
It comes with four Cortex-A53 cores in a singe cluster and the usual
peripherals for set-top box/tablet SoC.

The ATF platform target is called "sun50i_a64".

[Andre: adapted to amended directory layout, removed unneeded definitions ]

Signed-off-by: Samuel Holland <samuel@sholland.org>
Signed-off-by: Andre Przywara <andre.przywara@arm.com>