[lld] [lld][LoongArch] Convert TLS IE to LE in the normal or medium code model (PR #123680)

[Lu Weining via llvm-commits]

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

My comments are addressed. No sure whether other people have any comments especially for `Relocations.cpp`?

https://github.com/llvm/llvm-project/pull/123680