Revert "nouveau: push event block/allowing out of the fence context"

This reverts commit eacabb54

.

This commit causes some regressions in desktop usage, this will
reintroduce the original deadlock in DRI_PRIME situations, I've
got an idea to fix it by offloading to a workqueue in a different
spot, however this code has a race condition where we sometimes
miss interrupts so I'd like to fix that as well.

Cc: stable@vger.kernel.org
Signed-off-by: Dave Airlie <airlied@redhat.com>