[clang] Fix build break in SemaHLSL.cpp on MSVC 2022: warning C4715: 'getResourceClass': not all control paths return a value (PR #112767)

[Helena Kotas via cfe-commits]

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

LGTM, thank you for the fix! Interesting that it fires up, the switch covers all enum values.

https://github.com/llvm/llvm-project/pull/112767