[lld] [lld][LoongArch] Relax R_LARCH_PCALA_HI20 and R_LARCH_PCALA_LO12 (PR #112696)

[via llvm-commits]

ywgrit wrote:

> Basically it looks good to me. But I'd like to know how did you test the relaxation functionality? For example, use gcc(with relax enabled) + lld to build some programs?
Yes. Here's the details of my testing process.
1. Build gcc-1/llvm-project-1 with gcc(comes from LoongArch Upstream Package) and lld(relaxed)
2. Build gcc-2 with gcc-1 and lld
3. Build llvm-project-2 with clang-1(the part of llvm-project-1) and lld
4. Build redis/mysql/postgres and some other large programs that are very commonly used with gcc/clang(comes from LoongArch Upstream Package) and lld.
5. Test basic functionality of gcc-2 and llvm-project-2, they are used to compiled redis/postgres/mysql

https://github.com/llvm/llvm-project/pull/112696