[clang] [HLSL] set alwaysinline on HLSL functions (PR #106588)

[Damyan Pepper via cfe-commits]

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

LGTM, but would be good to get a review from someone more knowledgeable in the area than I am.

https://github.com/llvm/llvm-project/pull/106588