frv minmax predicate

[DJ Delorie]

> You just have to make sure that the predicate only accepts the types
> of operands the insn and constraints are prepared to handle.  I would
> be a little bit skeptical of removing the gpr_or_int10_operand test,
> for example.  But it would be reasonable to check something else for a
> floating point mode.

That was my concern too, but the define_insn_and_split *also* has the
predicates for the operands.  Do they need to be duplicated?