[clang] [clang-linker-wrapper] Re-use type returned from 'PointerType::getUnqual(C)' (NFC) (PR #73374)

[Joseph Huber via cfe-commits]

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

Thanks, this was never properly cleaned up after moving to opaque pointers.

https://github.com/llvm/llvm-project/pull/73374