tcp_input: if tcp->req > recvreq, send ack only when state is TCP_ESTABLISHED

we will drop packet when tcp_close_eventhandler
is register and invoke by tcp_input. then we will always early return and
never stop, the peer will only close the connection if we send reset packet.

precondition:
close -> register tcp_close_eventhandler;

tcp_input -> tcp_callback(TCP_NEWDATA) -> devif_conn_event -> tcp_close_eventhandler
-> flags &= ~TCP_NEWDATA -> NOT entry tcp_data_event -> conn->recvreq NOT increase

old flow:
tcp_input -> tcp->seqno greater than conn->rcvseq -> tcp_send(TCP_ACK)

with this patch:
tcp_input -> tcp->seqno greater than conn->rcvseq -> !TCP_ESTABLISHED
-> case TCP_FIN_WAIT_1 -> dev->d_len greater than 0 -> tcp_reset

Signed-off-by: zhanghongyu <zhanghongyu@xiaomi.com>

net/tcp/tcp_input.c

@@ -1214,7 +1214,7 @@ found:
                   return;
                 }
             }
-          else
+          else if ((conn->tcpstateflags & TCP_STATE_MASK) <= TCP_ESTABLISHED)
             {
 #ifdef CONFIG_NET_TCP_OUT_OF_ORDER
               /* Queue out-of-order segments. */