tweak trace logging

Author: tlyu

cores/arduino/USBCore.cpp

@@ -1030,13 +1030,13 @@ void USBCore_::transcOut(usb_dev* usbd, uint8_t ep)
     auto count = transc->xfer_count;
     USBCore().logEP(':', ep, '<', count);
     if (ep == 0) {
-        uint8_t buf[USBD_EP0_MAX_SIZE];
-        uint8_t count = usbd->drv_handler->ep_read(buf, 0U, EP_BUF_SNG);
         if (count != 0) {
             if (usbd->control.ctl_state == USBD_CTL_STATUS_OUT) {
+                uint8_t buf[USBD_EP0_MAX_SIZE];
+                uint8_t count = usbd->drv_handler->ep_read(buf, 0U, EP_BUF_SNG);
                 USBCore().hexDump('!', buf, count);
             } else {
-                USBCore().hexDump('<', buf, count);
+                USBCore().hexDump('<', ctlBuf, count);
             }
         }
         this->oldTranscOut(usbd, ep);