CLEANUP: sock: always perform last connection updates before wakeup

CLEANUP: sock: always perform last connection updates before wakeup

Normally the task_wakeup() in sock_conn_io_cb() is expected to
happen on the same thread the FD is attached to. But due to the
way the code was arranged in the past (with synchronous callbacks)
we continue to update connections after the wakeup, which always
makes the reader have to think deeply whether it's possible or not
to call another thread there. Let's just move the tasklet_wakeup()
at the end to make sure there's no problem with that.