The cursor code may be entered with file_priv == NULL && handle == NULL.
The problem was introduced by:
"bf89209 drm/mga200g: Hold a proper reference for cursor_set"
which calls drm_gem_object_lookup(dev, file_priv...). Previously this wasn't
a problem because we checked the handle. Move the check early in the function
can fix the problem.
Signed-off-by: Rui Wang <rui.y.wang@intel.com> Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch> Signed-off-by: Dave Airlie <airlied@redhat.com>