Fix Ender 3 V2 encoder (#20784)

Marlin/src/lcd/dwin/e3v2/dwin.cpp

     valref += EncoderRate.encoderMoveValue;
   else if (encoder_diffState == ENCODER_DIFF_CCW)
     valref -= EncoderRate.encoderMoveValue;
-  else if (encoder_diffState == ENCODER_DIFF_ENTER)
-    return true;
+  return encoder_diffState == ENCODER_DIFF_ENTER;
 }
 
 //