Fix bug in constraint-check generator, reported by Rask Ingemann
	Lambertsen:
	* genpreds.c (add_constraint): Don't remove anything from the
	expression here.
	(write_tm_constrs_h): Detect whether "op" argument is used, and
	mark it ARG_UNUSED if it isn't.
	(write_insn_const_int_ok_for_constraint): Skip the part of the
	expression that would test whether "op" (which is not available
	here) is a CONST_INT.

From-SVN: r117433