st/nine: Resolve deadlock in surface/volume dtors when using csmt

st/nine: Resolve deadlock in surface/volume dtors when using csmt

Surfaces and Volumes can be freed in the worker thread.

Without this patch, pending_uploads_counter could be non-zero
in the Surfaces or Volumes dtor, leading to deadlock.
Instead decrease properly the counter before releasing the
item.

Also avoid another potential deadlock if the item is not
properly unlocked: Do not call UnlockRect which will cause deadlock,
but free directly using the deadlock safe
nine_context_get_pipe_multithread.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=99246

CC: "17.0" <mesa-stable@lists.freedesktop.org>
Signed-off-by: Axel Davy <axel.davy@ens.fr>
Tested-by: James Harvey <lothmordor@gmail.com>