Costmetic changes to networking logic

net/devif/devif_callback.c

@@ -257,7 +257,8 @@ void devif_callback_free(FAR struct net_driver_s *dev,
 
       /* Put the structure into the free list */
 
-      cb->nxtconn = g_cbfreelist;
+      cb->nxtconn  = g_cbfreelist;
+      cb->nxtdev   = NULL;
       g_cbfreelist = cb;
       net_unlock(save);
     }

net/socket/recvfrom.c

@@ -895,7 +895,7 @@ static uint16_t recvfrom_tcpinterrupt(FAR struct net_driver_s *dev,
 
           /* Wake up the waiting thread, returning either the error -EAGAIN
            * that signals the timeout event or the data received up to
-           * the point tht the timeout occured (no error).
+           * the point that the timeout occurred (no error).
            */
 
           sem_post(&pstate->rf_sem);