drm: Destroy the planes prior to destroying the associated CRTC

As during the plane cleanup, we wish to disable the hardware and
so may modify state on the associated CRTC, that CRTC must continue to
exist until we are finished.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=54101
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Jesse Barnes <jbarnes@virtuousgeek.org>
Cc: stable@vger.kernel.org
Reviewed-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Tested-by: lu hua <huax.lu@intel.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>

diff --cc drivers/gpu/drm/drm_crtc.c
Simple merge