[lld] r257023 - [ELF] Add AMDGPU support

[Rafael Espíndola via llvm-commits]

> I agree that MIPS is unusual architecture from the linker point of
> view. But other linkers like gold and mclinker have not too
> complicated design, fast and support MIPS together with other targets.
> I do not have ready solution for LLD but maybe ability to create
> target specific GOT sections, override iteration over relocations etc
> allow to isolate unusual MIPS code and does not pollute common code.

Sorry for not being clear, most of the pain I see is on the llvm side
(where r_info parsing is done and we have the joy of handling the ABIs
and their implementations in bfd).

Cheers,
Rafael