[lld] [lld][NFC] Silence -Wuninitialized GCC warnings. (PR #75183)

[Fangrui Song via llvm-commits]

MaskRay wrote:

> I believe clang does a better job with sometimes-ininitialized warnings, perhaps we should just disable GCC's overly conservative warning, rather than adding unnecessary initializers? (that would hinder Clang's better warning and sanitizer detections)

I agree. I have seen several instances that GCC `-Wuninitialized` is annoying than useful.

https://github.com/llvm/llvm-project/pull/75183