[compiler-rt] [llvm] [JITLink][Mips] Add ELF backend (PR #224578)

[Jiaxun Yang via llvm-commits]

FlyGoat wrote:

> Looks great @FlyGoat!
> 
> Just a heads up that work is progressing on the new ORC runtime (`llvm-project/orc-rt`). I think your work in this commit will port over naturally, but in the future we expect to add new features that may require more mips-specific code. Do you want me to ping you if/when that happens?

Sure, please keep me in the loop. I'm always happy to handle those Mips specific stuff to make sure Mips remain first class citizen here :-)

I'll handle those review comments latter.

https://github.com/llvm/llvm-project/pull/224578