The value for "LLVM llvm-as flags" is wrong

Summary

The patch that added SettingsLlvmAsFlags sets a wrong value: !14025 (diffs)

It leads to an invocation of clang-15 clang-15 -fno-PIC ... and results in an error like clang: error: no such file or directory: 'clang-15'.

Steps to reproduce

Configure GHC HEAD with the LLVM toolchain installed, and compile a program with -fllvm.

Expected behavior

The compiler should compile a program successfully.

Environment

• GHC version used: b3f80b07

Optional:

• Operating System: Ubuntu 22.04
• System Architecture: x86_64