add further boilerplate, missing functions for usb console

gat_stand_fw/user/periph/usb/cdc.c

@@ -345,3 +345,14 @@ void CDC_DataRx_Process( void )
         }
     }
 }
+
+__attribute__((interrupt("WCH-Interrupt-fast")))
+void TIM4_IRQHandler(void)
+{
+    // uart timeout counts
+    Cdc.Rx_TimeOut++;
+    Cdc.USB_Up_TimeOut++;
+
+    // clear status
+    TIM4->INTFR = (uint16_t)~TIM_IT_Update;
+}