drm_atomic_helper_cleanup_planes only calls the cleanup_fb plane
helpers, which we don't implement as a CMA framebuffer based driver.
There is no reason to wait for vblanks in commit_tail only to do nothing
afterwards.
Signed-off-by: NPhilipp Zabel <p.zabel@pengutronix.de>
Reviewed-by: NLucas Stach <l.stach@pengutronix.de>