[clang] [llvm] [clang][OMPIRBuilder] Fix reduction codegen for SPIR-V (PR #162529)

[Joseph Huber via cfe-commits]

https://github.com/jhuber6 approved this pull request.

Seems reasonable, I'm assuming the other targets have the same behavior as before since we don't split on function AS.

https://github.com/llvm/llvm-project/pull/162529