[AIX] Remove AixLinker's debuginfo() implementation

`-s` option doesn't perfectly fit into debuginfo()'s semantics and may unexpectedly
remove metadata in shared libraries. Remove the implementation and suggest user to
use `strip` utility instead.

Author: Kai Luo

compiler/rustc_codegen_ssa/src/back/linker.rs

@@ -1613,16 +1613,7 @@ impl<'a> Linker for AixLinker<'a> {
 
     fn control_flow_guard(&mut self) {}
 
-    fn debuginfo(&mut self, strip: Strip, _: &[PathBuf]) {
-        match strip {
-            Strip::None => {}
-            // FIXME: -s strips the symbol table, line number information
-            // and relocation information.
-            Strip::Debuginfo | Strip::Symbols => {
-                self.cmd.arg("-s");
-            }
-        }
-    }
+    fn debuginfo(&mut self, _: Strip, _: &[PathBuf]) {}
 
     fn no_crt_objects(&mut self) {}