target: fix powerpc64-unknown-linux-musl datalayout

In LLVM 17, PowerPC targets started including function pointer alignments
in data layouts, and in Rust's update to that version (rust-lang#114048), we added
the function pointer alignments. `powerpc64-unknown-linux-musl` had
`Fi64` set but this seems incorrect, and the code in LLVM would always
have computed `Fn32` because it is a MUSL target.

Signed-off-by: David Wood <david@davidtw.co>

Author: davidtwco

compiler/rustc_target/src/spec/targets/powerpc64_unknown_linux_musl.rs

@@ -11,7 +11,7 @@ pub fn target() -> Target {
     Target {
         llvm_target: "powerpc64-unknown-linux-musl".into(),
         pointer_width: 64,
-        data_layout: "E-m:e-Fi64-i64:64-n32:64-S128-v256:256:256-v512:512:512".into(),
+        data_layout: "E-m:e-Fn32-i64:64-n32:64-S128-v256:256:256-v512:512:512".into(),
         arch: "powerpc64".into(),
         options: TargetOptions { endian: Endian::Big, mcount: "_mcount".into(), ..base },
     }