Use multiply for delta probe constraint

Marlin/Marlin_main.cpp

             // If we have gone out too far, we can do a simple fix and scale the numbers
             // back in closer to the origin.
             while (HYPOT(X_current, Y_current) > DELTA_PROBEABLE_RADIUS) {
-              X_current /= 1.25;
-              Y_current /= 1.25;
+              X_current *= 0.8;
+              Y_current *= 0.8;
               if (verbose_level > 3) {
                 SERIAL_ECHOPAIR("Pulling point towards center:", X_current);
                 SERIAL_ECHOLNPAIR(", ", Y_current);