Feature/port avr build check (#35)

* fix atmega168 build.

* remove time.h to solve AVR compile

* Add AVR build to CI for compile check

ports/atmega168/h_wp.c

@@ -133,6 +133,7 @@ void handler_write_property(
     bytes_sent =
         datalink_send_pdu(src, &npdu_data, &Handler_Transmit_Buffer[0],
         pdu_len);
+    (void)bytes_sent;
 
     return;
 }