[llvm] [NFC][DirectX] Fix build failure (PR #155441)

[Finn Plummer via llvm-commits]

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

Thanks for catching this. Maybe you could update the commit message to include where it was found and the reason:

The `DirectX` backend incorrectly did not specify it's dependency on `BinaryFormat` as it was a header only dependency and so it did not cause any build failures.

https://github.com/llvm/llvm-project/pull/155441