Fix handling of large arguments passed by value.

Fix handling of large arguments passed by value.

2023-04-15  John David Anglin  <danglin@gcc.gnu.org>

gcc/ChangeLog:

	PR target/104989
	* config/pa/pa-protos.h (pa_function_arg_size): Update prototype.
	* config/pa/pa.cc (pa_function_arg): Return NULL_RTX if argument
	size is zero.
	(pa_arg_partial_bytes): Don't call pa_function_arg_size twice.
	(pa_function_arg_size): Change return type to int.  Return zero
	for arguments larger than 1 GB.  Update comments.