The BOs are eventually released by the cursor plane's destroy callback.
Signed-off-by: NThomas Zimmermann <tzimmermann@suse.de>
Acked-by: NGerd Hoffmann <kraxel@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210209134632.12157-5-tzimmermann@suse.de