gdb/testsuite/

	gdb/testsuite/
	* gdb.base/callfuncs.exp (do_function_calls): Use t_double_int
	and t_int_double.
	* gdb.base/callfuncs.c (t_double_int, t_int_double): New.

	gdb/
	* mips-tdep.c (mips_n32n64_fp_arg_chunk_p): New.
	(mips_n32n64_push_dummy_call): Always increment float_argreg along
	with argreg.  Use mips_n32n64_fp_arg_chunk_p.