reload question about unmet constraints

[DJ Delorie]

> So in general, it's really not safe to mark a constraint that accepts
> only far memory as "memory constraint" with current reload.
> 
> Note that *not* marking the constraint as memory constraint actually
> does not prevent reload from fixing up illegitimate addresses, so you
> shouldn't really see much drawbacks from not marking it ...

While working through the regressions on this one I discovered one
seemingly important side-effect...

For such constraints that are memory operands but not
define_memory_constraint, you need to use '*' to keep reload from
trying to guess a register class from them (it guesses wrong for
rl78).

I.e. use "*Wfr" instead of "Wfr".