[lld] [LLD][COFF] Add basic ARM64X dynamic relocations support (PR #118035)

[Martin Storsjö via llvm-commits]

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

LGTM, thanks!

Please mention and explain why the `.clear()` call is moved from `addBaserels()` in the commit message.

https://github.com/llvm/llvm-project/pull/118035