sunxi: add basic memory map definitions of H6 SoC

The Allwinner H6 SoC come with a totally new memory map.

Add basical definition of the new memory map into a header file, and let
the cpu.h header include it in the situation of H6.

Signed-off-by: Icenowy Zheng <icenowy@aosc.io>
Reviewed-by: Andre Przywara <andre.przywara@arm.com>
Acked-by: Maxime Ripard <maxime.ripard@bootlin.com>
Reviewed-by: Jagan Teki <jagan@openedev.com>
Tested-by: Jagan Teki <jagan@amarulasolutions.com>