Fix address violation parsing a corrupt Alpha VMS binary file.

Fix address violation parsing a corrupt Alpha VMS binary file.

	PR binutils/21639
	* vms-misc.c (_bfd_vms_save_sized_string): Use unsigned int as
	type of the size parameter.
	(_bfd_vms_save_counted_string): Add second parameter - the maximum
	length of the counted string.
	* vms.h (_bfd_vms_save_sized_string): Update prototype.
	(_bfd_vms_save_counted_string): Likewise.
	* vms-alpha.c (_bfd_vms_slurp_eisd): Update calls to
	_bfd_vms_save_counted_string.
	(_bfd_vms_slurp_ehdr): Likewise.
	(_bfd_vms_slurp_egsd): Likewise.
	(Parse_module): Likewise.