[mlir][bazel] Fix missing dependency in TransformOpsPyFiles.

[ingomueller-net]

Summary

This is necessary due to a new file introduced in
https://reviews.llvm.org/D155717 but the problem only showed up in some
bazel-based build downstream.

[ftynse]

Feel free to commit bazel fixes directly.

[ingomueller-net]

This was fixed by https://github.com/llvm/llvm-project/commit/e6c62a2d in the end, which was more elaborate that the one line from this patch.

utils/bazel/llvm-project-overlay/mlir/python/BUILD.bazel

deps = [
         "//mlir:TransformPDLExtensionTdFiles",
     ],
 )
 
 filegroup(
     name = "TransformOpsPyFiles",
     srcs = [
         "mlir/dialects/_loop_transform_ops_ext.py",
+        "mlir/dialects/_gpu_transform_ops_ext.py",
         "mlir/dialects/_structured_transform_ops_ext.py",
         "mlir/dialects/_transform_ops_ext.py",
         "mlir/dialects/_transform_pdl_extension_ops_ext.py",
         ":LoopTransformOpsPyGen",
         ":PDLTransformOpsPyGen",
         ":StructuredTransformOpsPyGen",
         ":TransformOpsPyGen",
     ],