[lld] [LLD][RISCV] Fix incorrect call relaxation when mixing +c and -c objects (PR #73977)

[Jessica Clarke via llvm-commits]

https://github.com/jrtc27 approved this pull request.

This makes sense to me, let's see what others think.

Of course, there's the bigger problem that we don't (currently) encode the arch string in R_RISCV_RELAX (which I've previously proposed by using the symbol to point at a mapping symbol or similar), but we do have _this_ information so should honour it.

https://github.com/llvm/llvm-project/pull/73977