sunxi: Add F1C100s DRAM initial support

Add support for F1C100s internal dram controller.

Signed-off-by: Icenowy Zheng <icenowy@aosc.io>
Signed-off-by: Jesse Taube <Mr.Bossman075@gmail.com>
Signed-off-by: Andre Przywara <andre.przywara@arm.com>