sunxi: add support for the Allwinner A100/A133 SoC

sunxi: add support for the Allwinner A100/A133 SoC

The Allwinner A100 SoC has been around for a while, mostly on cheap
tablets, but didn't generate much interest in the community so far.
There were some efforts by two Allwinner employees in 2020, which led
to basic upstream Linux support for that SoC, although this momentum
dried up pretty quickly, leaving a lot of peripherals unsupported.

The A100 was silently replaced with the seemingly identical Allwinner
A133, which is reportedly a better bin of the A100. So far we assume
that both are compatible from a software perspective. There are some
more devices with the A133 out there now, so people are working on
filling the gaps, and adding U-Boot (and TF-A) support.

Based on the just added pinctrl, clock and DRAM support, this adds the
missing bits, mostly addresses and values for the SPL.

The A133 seems to be an predecessor to the H6, so we can share a lot of
code with that (and the H616 code), and just need to adjust some details.

Signed-off-by: Andre Przywara <andre.przywara@arm.com>