* elfxx-target.h (bfd_elfNN_canonicalize_reloc): Make it

* elfxx-target.h (bfd_elfNN_canonicalize_reloc): Make it
overridable.
* elf64-mips.c (mips_elf64_canonicalize_reloc,
mips_elf64_get_dynamic_reloc_upper_bound,
mips_elf64_canonicalize_dynamic_reloc): New, adapted from elf.c.
(bfd_elf64_get_canonicalize_reloc,
bfd_elf64_get_dynamic_reloc_upper_bound,
bfd_elf64_canonicalize_dynamic_reloc): Define.
(mips_elf64_slurp_reloc_table): Support dynamic.
(mips_elf64_slurp_one_reloc_table): Adjust.