[clang] [Clang][LoongArch] Fixed incorrect _BitInt(N>64) alignment (PR #145297)

[Lu Weining via cfe-commits]

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

LGTM. BTW, could you please mention this change in clang's release note?

https://github.com/llvm/llvm-project/pull/145297