[llvm] [RISCV] fixup_riscv_rvc_imm may be linker relaxable (PR #161797)

[Sam Elliott via llvm-commits]

lenary wrote:

I believe I have addressed all feedback and I have an approval. I plan to land this in 24 hours unless I get more feedback. 

https://github.com/llvm/llvm-project/pull/161797