[llvm] [Support] FIx a warning (PR #138546)

[Kazu Hirata via llvm-commits]

kazutakahirata wrote:

> Do we enable this warning?

I don't enable just this warning in particular, but I'm using clang-19.1.7 with `-DLLVM_ENABLE_WERROR=On`.  That seems to include this warning.


https://github.com/llvm/llvm-project/pull/138546