PR target/14758

	PR target/14758
bfd/
	* elf32-ppc.c (ppc_elf_reloc_type_lookup): Decode ppc64 _DS
	bfd_reloc values.  Map to corresponding D-form relocs.
	(is_insn_ds_form, is_insn_qs_form): New functions.
	(ppc_elf_relocate_section): Validate insn with DS-form or DQ-form
	fields using D-form reloc.
gas/
	* config/tc-ppc.c (ppc_setup_opcodes): Fix comment.
	(md_assemble): Translate to _DS relocs for ppc32 as well as ppc64.
	(tc_gen_reloc): Handle _DS relocs in ppc32 mode.