message: Integrate LLVM at llvm/llvm-project@54ec9bb5510d
  Updates LLVM usage to match
  [54ec9bb5510d](https://github.com/llvm/llvm-project/commit/54ec9bb5510d)
diff: @@ -686,8 +686,8 @@ def tf_repositories(path_prefix = "", tf_repo_name = ""):
  )
  # Check out LLVM and MLIR from llvm-project.
  - LLVM_COMMIT = "dc35368ccf17a7dca0874ace7490cc3836fb063f"
  - LLVM_SHA256 = "fb5390d975698bee0756d6049adf5ba1218c2bcb150fad892f211848d0f9db42"
  + LLVM_COMMIT = "54ec9bb5510de301d05e8b34bb8c2484e8c95eaa"
  + LLVM_SHA256 = "99f113ed7f0cec75d38373d4ecd0ea8ee8aace1d73360014daa4423aee01ff6a"
  LLVM_URLS = [
  "https://storage.googleapis.com/mirror.tensorflow.org/github.com/llvm/llvm-project/archive/{commit}.tar.gz".format(commit = LLVM_COMMIT),
  "https://github.com/llvm/llvm-project/archive/{commit}.tar.gz".format(commit = LLVM_COMMIT),
  