[rfa/mips] Second go at vr5500 hilo hazard fix

[Richard Sandiford]

cgd@broadcom.com writes:
> And he and I (strongly, IMO) disagreed at that time.  (IIRC, I think I
> mentioned at the time that the right solution to this is better
> testing.  I still think that's true.)
>
> Of course, in August of last year, (unprompted by me!) he decided to
> stop being MIPS co-maintainer.  So, at this point, I'm the approval
> authority, and I like my style of patch most.  8-)

Well, so far I've done it your way, and had it rejected by Andrew, and
I've done it Andrew's way and had it rejected by you. ;)  I'd like to
make sure there's now some agreement before going ahead and updating
the original MIPS_MACH version.

So, Andrew, is it OK with you to have a bfd_mach check in mips.igen?
As per previous discussion, we'd have something like:

    if (MIPS_MACH (SD) == bfd_mach_mips5500)
      ...

Even if it's not how you'd recommend it be done, is it at least
something you can accept?

Richard