start-sanitize-r5900

start-sanitize-r5900
	The value of R_MIPS15_S3 has changed:
	* elf32-mips.c (elf_mips15_s3_howto): New static variable.
	(mips_reloc_map): Remove BFD_RELOC_MIPS15_S3.
	(bfd_elf32_bfd_reloc_type_lookup): Handle BFD_RELOC_MIPS15_S3
	specially.
	(mips_info_to_howto_rel): Handle R_MIPS15_S3 specially.
	(mips_elf_relocate_section): Check for R_MIPS15_S3.

end-sanitize-r5900
	* elf32-mips.c (elf_mips_howto_table): Add reloc types used on
	Irix 6.
	(bfd_elf32_bfd_reloc_type_lookup): Add default case.
	* elf64-mips.c: Replace all uses of mips_elf64_reloc_type with
	elf_mips_reloc_type defined in elf/mips.h.