sunxi: add support for Lichee Pi Zero

Lichee Pi Zero is a development board with a V3s SoC, which features
64MiB DRAM co-packaged within the SoC, a TF slot, a SPI NOR slot (not
soldered in production batch), a 40-pin RGB LCD connector and some extra
pins available as 2.54mm pins or stamp holes.

Add support for it.

Signed-off-by: Icenowy Zheng <icenowy@aosc.io>
Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>