Fix copy-and-paste error in exception message.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@120033 91177308-0d34-0410-b5e6-96231b3b80d8

utils/TableGen/NeonEmitter.cpp

@@ -89,7 +89,7 @@ static char Narrow(const char t) {
       return 'i';
     case 'f':
       return 'h';
-    default: throw "unhandled type in widen!";
+    default: throw "unhandled type in narrow!";
   }
   return '\0';
 }