drm/ttm: flip the switch, and convert to dma_fence

drivers/gpu/drm/nouveau/nouveau_bo.c

drivers/gpu/drm/nouveau/nouveau_fence.c

drivers/gpu/drm/nouveau/nouveau_fence.h

drivers/gpu/drm/nouveau/nouveau_gem.c

drivers/gpu/drm/qxl/qxl_debugfs.c

drivers/gpu/drm/qxl/qxl_drv.h

drivers/gpu/drm/qxl/qxl_kms.c

drivers/gpu/drm/qxl/qxl_object.h

drivers/gpu/drm/qxl/qxl_release.c

drivers/gpu/drm/qxl/qxl_ttm.c

drivers/gpu/drm/radeon/radeon_cs.c

drivers/gpu/drm/radeon/radeon_display.c

drivers/gpu/drm/radeon/radeon_mn.c

drivers/gpu/drm/radeon/radeon_object.c

drivers/gpu/drm/radeon/radeon_ttm.c

drivers/gpu/drm/radeon/radeon_uvd.c

drivers/gpu/drm/radeon/radeon_vm.c

drivers/gpu/drm/ttm/ttm_bo.c

drivers/gpu/drm/ttm/ttm_bo_util.c

drivers/gpu/drm/ttm/ttm_execbuf_util.c