syslog: fixed building syslog-disabled firmware

modules/syslog.h

@@ -6,6 +6,7 @@ void syslog(char *fmt, ...);
 void syslog_str(char *msg);
 #else // defined(HARDWARE_BT6711) && !defined(BT6702_SERVICE)
 #define openlog()
+#define syslog(...)
 #define syslog_str(msg)
 #endif // defined(HARDWARE_BT6711) && !defined(BT6702_SERVICE)
 #endif // __SYSLOG_H__