Merge https://source.denx.de/u-boot/custodians/u-boot-sunxi

This contains some fixes, and the first bunch of some clean up patches
to get rid of legacy GPIO and PMIC code.
Highlight is the DM AXP PMIC driver, which is required to convert some
drivers over to use DM regulators, and also is required to get rid
of some less optimal PMIC setup code in Trusted Firmware. This isn't
enabled by any defconfig yet, but can be enabled manually and works. For
the full glory some patches are still missing, and this requires more
testing, which would be simpler if the core code is upstream.