[clang] [HLSL] Fix for build break introduced by #85662 (PR #85839)

[Justin Bogner via cfe-commits]

bogner wrote:

I've gone ahead and merged this since it fixes the build break. In the future when you see a build break, please just revert the breaking change to get the build green again and then work on the fixed patch. It's unfair to others using trunk to have to wait on a fix for an obvious build break.

https://github.com/llvm/llvm-project/pull/85839