Add missing 'return on failure'. Previously we'd crash after emitting

the diagnostic.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@127480 91177308-0d34-0410-b5e6-96231b3b80d8

utils/TableGen/TGParser.cpp

@@ -1153,6 +1153,7 @@ Init *TGParser::ParseSimpleValue(Record *CurRec, RecTy *ItemType) {
         s << "Type mismatch for list, expected list type, got "
           << ItemType->getAsString();
         TokError(s.str());
+        return 0;
       }
       GivenListTy = ListType;
     }