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>
diff --git a/maintainers.rst b/maintainers.rst
index 2217cbe..9b0599e 100644
--- a/maintainers.rst
+++ b/maintainers.rst
@@ -64,6 +64,16 @@
 -  plat/hisilicon/hikey/\*
 -  plat/hisilicon/hikey960/\*
 
+Allwinner ARMv8 platform sub-maintainer
+---------------------------------------
+
+Andre Przywara (andre.przywara@arm.com, `Andre-ARM`_)
+
+Files:
+
+-  docs/plat/allwinner.rst
+-  plat/allwinner/\*
+
 HiSilicon Poplar platform sub-maintainer
 ----------------------------------------
 
@@ -151,3 +161,4 @@
 .. _rockchip-linux: https://github.com/rockchip-linux
 .. _etienne-lms: https://github.com/etienne-lms
 .. _qoriq-open-source: https://github.com/qoriq-open-source
+.. _Andre-ARM: https://github.com/Andre-ARM