[llvm] [NFC][LLVM] Use namespace `Intrinsic` in `Intrinsics.cpp` (PR #114822)

[Adrian Kuegel via llvm-commits]

akuegel wrote:

Agree, it is definitely surprising and I cannot explain it. But we have created a patch with the revert for Tensorflow (which was also affected), and that fixed the build.

https://github.com/llvm/llvm-project/pull/114822