Revert "Allow ttValue in qsearch"

This reverts commit 3f8aa4a.

Since the clamping with probcutbeta, the position can now be found as a mate.

src/search.cpp

@@ -1401,7 +1401,7 @@ Value Search::Worker::qsearch(Position& pos, Stack* ss, Value alpha, Value beta,
               to_corrected_static_eval(unadjustedStaticEval, *thisThread, pos);
 
             // ttValue can be used as a better position evaluation (~13 Elo)
-            if (ttData.value != VALUE_NONE
+            if (std::abs(ttData.value) < VALUE_MATE_IN_MAX_PLY
                 && (ttData.bound & (ttData.value > bestValue ? BOUND_LOWER : BOUND_UPPER)))
                 bestValue = ttData.value;
         }