sun8i: Add dram initialization support

Based on the register / dram_para headers from the Allwinner u-boot / linux
sources + the init sequences from boot0.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
sun8i: Add defconfig for Ippo_q8h v1.2

We need separate defconfigs for the v5 and v1.2 versions of this board, as
they use different DRAM parameters.

Note they also use different dtb files, as the wifi is different too.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>