net: support being a TCP server to unblock TCP fastboot

net: support being a TCP server to unblock TCP fastboot

Make following changes to unblock TCP fastboot support:

1. Implement being a TCP server support
2. Introduce dedicated TCP traffic handler (get rid of UDP signature)
3. Ensure seq_num and ack_num are respected in net_send_tcp_packet
function (make sure existing wget_cmd code is reflected with the fix)

Signed-off-by: Dmitrii Merkurev <dimorinny@google.com>
Cc: Ying-Chun Liu (PaulLiu) <paul.liu@linaro.org>
Cc: Simon Glass <sjg@chromium.org>
Сс: Joe Hershberger <joe.hershberger@ni.com>
Сс: Ramon Fried <rfried.dev@gmail.com>
Reviewed-by: Ying-Chun Liu (PaulLiu) <paul.liu@linaro.org>
Reviewed-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Ramon Fried <rfried.dev@gmail.com>