MEDIUM: queue: revert to regular inter-task wakeups

MEDIUM: queue: revert to regular inter-task wakeups

Now that the inter-task wakeups are cheap, there's no point in using
task_instant_wakeup() anymore when dequeueing tasks. The use of the
regular task_wakeup() is sufficient there and will preserve a better
fairness: the test that went from 40k to 570k RPS now gives 580k RPS
(down from 585k RPS with previous commit). This essentially reverts
commit 27fab1dcb ("MEDIUM: queue: use tasklet_instant_wakeup() to
wake tasks").