Currently in our shrinker path we shouldn't be encountering anything
that is active, but this will change in subsequent patches.  So check
if there are unsignaled fences.
Signed-off-by: Rob Clark <robdclark@chromium.org>
Patchwork: https://patchwork.freedesktop.org/patch/496117/
Link: https://lore.kernel.org/r/20220802155152.1727594-5-robdclark@gmail.com