Qualify one more make_unique call.

The previous patch had effect, but missed this one. It seems MSVC
gets ADL-confused by the calls where the first argument is a function call?

llvm-svn: 222968
diff --git a/llvm/lib/TableGen/TGParser.cpp b/llvm/lib/TableGen/TGParser.cpp
index cef7f96..d0c50d9 100644
--- a/llvm/lib/TableGen/TGParser.cpp
+++ b/llvm/lib/TableGen/TGParser.cpp
@@ -2169,8 +2169,8 @@
                       + "' already defined");
   } else {
     // If this is the first reference to this class, create and add it.
-    auto NewRec = make_unique<Record>(Lex.getCurStrVal(), Lex.getLoc(),
-                                      Records);
+    auto NewRec =
+        llvm::make_unique<Record>(Lex.getCurStrVal(), Lex.getLoc(), Records);
     CurRec = NewRec.get();
     Records.addClass(std::move(NewRec));
   }