This cmdline argument is now a no-op. Drop it everywhere and add a new
CI check to enforce this.

Adjust the deprecated "minimal" initramfs variant to use
pmos.debug-shell to enable logging instead. It doesn't /support/
dropping to a shell, so the variable takes on a different meaning. But
that's ok since it's at least more consistent.

[ci:ignore-count]
[ci:skip-vercheck]
Signed-off-by: Caleb Connolly <caleb@postmarketos.org>
Tweaked-by: Oliver Smith <ollieparanoid@postmarketos.org>
[ci:skip-build]: kernel builds are very likely to go through now