[PATCH][gold] PR 21111: Mips: Add HIGHER and HIGHEST relocations

[Cary Coutant]

Added to ChangeLog:

         PR gold/21111

>         * mips.cc (Mips_relocate_functions::relhigher): New method.
>         (Mips_relocate_functions::relhighest): Likewise.
>         (mips_get_size_for_reloc): Add support for relocs: R_MIPS_HIGHER and
>         R_MIPS_HIGHEST.
>         (Target_mips::Scan::local): Add support for relocs: R_MIPS_HIGHER,
>         R_MIPS_HIGHEST, R_MICROMIPS_HIGHER and R_MICROMIPS_HIGHEST.
>         (Target_mips::Scan::global): Likewise.
>         (Target_mips::Scan::get_reference_flags): Likewise.
>         (Target_mips::Relocate::relocate): Call static methods for resolving
>         HIGHER and HIGHEST relocations.

Committed on your behalf.

Thanks!

-cary