* elf32-mips.c: Remove superfluous definitions copied from

	* elf32-mips.c: Remove superfluous definitions copied from
	elfxx-mips.c.
	(bfd_elf32_bigmips_vec,bfd_elf32_littlemips_vec): Use the
	SGIish vectors to check the special case.
	(mips_elf_hi16_reloc): Fix comment.
	(mips_elf_got16_reloc): Likewise.
	(_bfd_mips_elf32_gprel16_reloc): Likewise.
	(elf_reloc_map): Code cleanup.
	(mips_reloc_map): Add comment.
	(bfd_elf23_bfd_reloc_type_lookup): Code cleanup.
	(mips_elf32_rtype_to_howto): Likewise.
	(mips_elf32_discard_info): Likewise.
	(elf32_mips_irix_compat): Invert logic: Only SGIish vectors
	lead to IRIX compatibility now.