[llvm] [LoongArch] Emit R_LARCH_RELAX when expanding some macros (PR #120067)

[via llvm-commits]

https://github.com/wangleiat commented:

This looks quite simple, except for one question: for macros that can be relaxed, do we unconditionally add the `R_LARCH_RELAX` relocation?

https://github.com/llvm/llvm-project/pull/120067