fix compile error include watchdog and uart configure error

Ubiquitous/XiZi/board/stm32f407-st-discovery/third_party_driver/watchdog/connect_wdg.c

@@ -86,6 +86,17 @@ static const struct WdtDevDone dev_done =
     NONE,
 };
 
+/**
+ * @description: Watchdog function
+ * @return success: EOK, failure: other
+ */
+int StartWatchdog(void)
+{
+    //add feed watchdog task function
+
+    return EOK;
+}
+
 /**
  * This function                            Watchdog initialization
  *