Simplify Time Management Formula

Decreasing the number of operations
Passed STC:
LLR: 2.97 (-2.94,2.94) <-1.75,0.25>
Total: 38880 W: 10038 L: 9823 D: 19019
Ptnml(0-2): 92, 4334, 10395, 4505, 114
https://tests.stockfishchess.org/tests/view/67112bf586d5ee47d953c6be

Passed LTC:
LLR: 2.94 (-2.94,2.94) <-1.75,0.25>
Total: 242844 W: 61425 L: 61431 D: 119988
Ptnml(0-2): 145, 25175, 70797, 25151, 154
https://tests.stockfishchess.org/tests/view/6712387486d5ee47d953c737

closes #5655

Bench: 1281912

src/search.cpp

@@ -443,9 +443,9 @@ void Search::Worker::iterative_deepening() {
         {
             int nodesEffort = rootMoves[0].effort * 100 / std::max(size_t(1), size_t(nodes));
 
-            double fallingEval = (1067 + 223 * (mainThread->bestPreviousAverageScore - bestValue)
-                                  + 97 * (mainThread->iterValue[iterIdx] - bestValue))
-                               / 10000.0;
+            double fallingEval = (11 + 2 * (mainThread->bestPreviousAverageScore - bestValue)
+                                  + (mainThread->iterValue[iterIdx] - bestValue))
+                               / 100.0;
             fallingEval = std::clamp(fallingEval, 0.580, 1.667);
 
             // If the bestMove is stable over several iterations, reduce time accordingly