Remove htons(); it is provided elsewhere in Etherboot

src/proto/uip/uip.c

@@ -1494,11 +1494,4 @@ uip_process(u8_t flag)
   uip_len = 0;
   return;
 }
-/*-----------------------------------------------------------------------------------*/
-u16_t
-htons(u16_t val)
-{
-  return HTONS(val);
-}
-/*-----------------------------------------------------------------------------------*/
 /** @} */