A foolish consistency is the hobgoblin of little minds, adored by
little statesmen and philosophers and divines. With consistency a
great soul has simply nothing to do. -- Ralph Waldo Emerson
the powerpc/ subdirectory. These have never used by SPARC and we have
no other (and almost certainly will have no other) Open Firmware platforms.
This makes the directory structure simpler and lets us avoid some
cargo-cult MI patterns on code that is, and always was,
architecture-specific.