sim: cgen: add remainder functions (needed for OR1K lf.rem.[sd])

sim: cgen: add remainder functions (needed for OR1K lf.rem.[sd])

* sim/common/ChangeLog:

2017-12-12  Peter Gavin  <pgavin@gmail.com>
	    Stafford Horne <shorne@gmail.com>

	* cgen-accfp.c (remsf, remdf): New function.
	(cgen_init_accurate_fpu): Add remsf and remdf.
	* cgen-fpu.h (cgen_fp_ops): Add remsf, remdf, remxf and remtf.
	* sim-fpu.c (sim_fpu_rem): New function.
	* sim-fpu.h (sim_fpu_status_invalid_irx): New enum.
	(sim_fpu_rem): New function.
	(sim_fpu_print_status): Add case for sim_fpu_status_invalid_irx.