[clang] [Clang][attr] Add 'cfi_salt' attribute (PR #141846)

[Erich Keane via cfe-commits]

================
@@ -7941,6 +7942,32 @@ static bool handleFunctionTypeAttr(TypeProcessingState &state, ParsedAttr &attr,
     return true;
   }
 
+  if (attr.getKind() == ParsedAttr::AT_CFISalt) {
+    if (attr.getNumArgs() == 0)
----------------
erichkeane wrote:

```suggestion
    if (attr.getNumArgs() != 1)
```

Perhaps?  Alternatively, should this be an `assert(attr.getNumArgs() == 1)` ? 

https://github.com/llvm/llvm-project/pull/141846