sunxi: add basic V3s support

sunxi: add basic V3s support

Basic U-Boot support is now present for V3s.

Some memory addresses are changed specially for V3s, as the original
address map cannot fit into a so small DRAM.

As the DRAM controller code needs a big refactor, the SPL support is
disabled in this version.

Signed-off-by: Icenowy Zheng <[email protected]>
Acked-by: Maxime Ripard <[email protected]>
Reviewed-by: Jagan Teki <[email protected]>
Signed-off-by: Maxime Ripard <[email protected]>