[lld] [llvm] [RISCV] Support RISCV Atomics ABI attributes (PR #84597)

[Fangrui Song via llvm-commits]

MaskRay wrote:

> @MaskRay @asb Are we happy w/ this patch? I think I've addressed most of the concerns raised thus far, but I want try and finish the attributes patches this week if possible, since I'm back from EuroLLVM + vacation.

I am sorry it took a long time for me to notice the discussion and make some comments about the linker code.
While I appreciate the LGTM, given the number of linker comments I had to give,  landing this 7 hours after LGTM feels a bit rushed.

https://github.com/llvm/llvm-project/pull/84597