struct nouveau_sched contains a waitque needed to prevent
drm_sched_fini() from being called while there are still jobs pending.
Doing so so far would have caused memory leaks.
With the new memleak-free mode of operation switched on in
drm_sched_fini() by providing the callback
nouveau_sched_fence_context_kill() the waitque is not necessary anymore.
Remove the waitque.
Signed-off-by: Philipp Stanner <phasta@xxxxxxxxxx>