Merge from projects/mips to head by hand:
Copy over the support files (except sys/conf and sys/mips/conf) for
RMI XLR processor support. This port has been contributed by RMI and
brought up to date by Randal Stewart (rrs@). This port is a work in
progress, and there might still be significant changes. The port
makes it to multi-user, but is still early beta.