re PR target/14567 ([3.4 only] long double and va_arg complex args)

re PR target/14567 ([3.4 only] long double and va_arg complex args)

	PR target/14567
	* config/rs6000/rs6000.h (UNITS_PER_ARG, RS6000_ARG_SIZE): Delete.
	(HARD_REGNO_MODE_OK): Disallow TFmode for fp31.
	* config/rs6000/rs6000.c (rs6000_arg_size): New function.
	Update all users of RS6000_ARG_SIZE.
	(function_arg_advance): Count fregno using mode size.
	(function_arg): Handle long double split over regs and memory.
	(function_arg_partial_nregs): Likewise.
	(rs6000_va_arg): Repackage complex args.

From-SVN: r79436