Fix a race in pondering mode

Fixes an hang when playing with ponder ON. Perhaps there is still
a very small race but now it seems engine does not hang anymore.

No functional change.

Signed-off-by: Marco Costalba <mcostalba@gmail.com>

src/uci.cpp

@@ -82,10 +82,9 @@ void uci_loop() {
           Search::Limits.ponder = false; // FIXME racing
 
           if (Search::Signals.stopOnPonderhit)
-          {
               Search::Signals.stop = true;
-              Threads[0].wake_up(); // In case is waiting for stop or ponderhit
-          }
+
+          Threads[0].wake_up(); // In case is waiting for stop or ponderhit
       }
 
       else if (token == "go")