[llvm] [mlir] [mlir] NFC: Fix layering check / parse headers violations (PR #110117)

[Mehdi Amini via llvm-commits]

joker-eph wrote:

I don't understand why the change in the source file is needed? Why would the build be successful with CMake but not with Bazel? 

https://github.com/llvm/llvm-project/pull/110117