ARM: unused boardfile removal for 6.3

This is a follow-up to the deprecation of most of the old-style board
files that was merged in linux-6.0, removing them for good.

This branch is almost exclusively dead code removal based on those
annotations. Some device driver removals went through separate subsystem
trees, but the majority is in the same branch, in order to better handle
dependencies between the patches and avoid breaking bisection.

Unfortunately that leads to merge conflicts against other changes in the
subsystem trees, but they should all be trivial to resolve by removing
the files.

See commit 7d0d3fa7339e ("Merge tag 'arm-boardfiles-6.0' of
git://git.kernel.org/pub/scm/linux/kernel/git/soc/soc") for the
description of which machines were marked unused and are now removed. The
only removals that got postponed are Terastation WXL (mv78xx0) and
Jornada720 (StrongARM1100), which turned out to still have potential
users.