drm/ttm: remove the backing store if no placement is given

Pipeline removal of the BOs backing store when no placement is given
during validation.

Signed-off-by: Christian König <christian.koenig@amd.com>
Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/353994/?series=73646&rev=1
1 file changed