[clang] [clang][RISCV] Fix clang dwarf info generation for unprtototyped function (PR #150022)

[Eli Friedman via cfe-commits]

https://github.com/efriedma-quic commented:

The code change looks fine.

Are the tests just checking that there's `!dbg` metadata attached to the function declarations?  Do you really need 12 RUN lines to check that?

https://github.com/llvm/llvm-project/pull/150022