Disable packaging of the (removed) MHLO extension. (#11299)

diff --git a/compiler/setup.py b/compiler/setup.py
index e71787a..9866c57 100644
--- a/compiler/setup.py
+++ b/compiler/setup.py
@@ -391,7 +391,9 @@
         CMakeExtension("iree.compiler._mlir_libs._mlir"),
         CMakeExtension("iree.compiler._mlir_libs._ireeDialects"),
         CMakeExtension("iree.compiler._mlir_libs._ireecTransforms"),
-        CMakeExtension("iree.compiler._mlir_libs._mlirHlo"),
+        # TODO: MHLO has been broken for a while so disabling. If re-enabling,
+        # it also needs to be enabled on the build side.
+        # CMakeExtension("iree.compiler._mlir_libs._mlirHlo"),
         CMakeExtension("iree.compiler._mlir_libs._mlirLinalgPasses"),
     ],
     cmdclass={