ARM: SoC platform updates

SoC changes, a substantial part of this is cleanup of some of the older
platforms that used to have a bunch of board files. In particular:

 - Removal of non-DT i.MX platforms that haven't seen activity in years,
   it's time to remove them.
 - A bunch of cleanup and removal of platform data for TI/OMAP platforms,
   moving over to genpd for power/reset control (yay!)
 - Major cleanup of Samsung S3C24xx and S3C64xx platforms, moving them
   closer to multiplatform support (not quite there yet, but getting
   close).

THere are a few other changes too, smaller fixlets, etc. For new
platform support, the primary ones re:

 - New SoC: Hisilicon SD5203, ARM926EJ-S platform.
 - Cpufreq support for i.MX7ULP