Merge branch 'drm-ttm-next' into drm-core-next

Merge branch 'drm-ttm-next' into drm-core-next

* drm-ttm-next:
  drm/radeon: Use the ttm execbuf utilities
  drm/ttm: Fix up io_mem_reserve / io_mem_free calling
  drm/ttm/vmwgfx: Have TTM manage the validation sequence.
  drm/ttm: Improved fencing of buffer object lists
  drm/ttm/radeon/nouveau: Kill the bo lock in favour of a bo device fence_lock
  drm/ttm: Don't deadlock on recursive multi-bo reservations
  drm/ttm: Optimize ttm_eu_backoff_reservation
  drm/ttm: Use kref_sub instead of repeatedly calling kref_put
  kref: Add a kref_sub function
  drm/ttm: Add a bo list reserve fastpath (v2)