co-processor. This is necessary so we can have several handlers for
CP0 (used as a catch-all for non-CP instructions).
Handlers are now removed using remove_coproc_handler(), rather than by calling
install_coproc_handler() with a NULL handler.
Because install_coproc_handler() can now allocate memory, there's a version
for use at boot time that doesn't.
tree into the new arm substree. All moved files are relinked with a stub that included
the file from the new location; this might be done better later.