[clang] [llvm] [PowerPC] Support local-dynamic TLS relocation on AIX (PR #66316)

[Amy Kwan via cfe-commits]

================
@@ -139,6 +139,12 @@ class ModulePass;
     /// and Local Exec models.
     MO_TPREL_FLAG,
 
+    /// MO_TLSLDM_FLAG - on AIX the ML relocation type is only valid for a
+    /// reference to a TOC symbol from the symbol itself, and right now its only
+    /// user is the symbol "_$TLSML". The symbol name is used to decide that
+    /// R_TLSML is expected.
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amy-kwan wrote:

nit:
```suggestion
    /// the R_TLSML relocation is expected.
```

https://github.com/llvm/llvm-project/pull/66316