drm/ttm: remove unused backend flags field

This field is not use by any of the driver just drop it.
Signed-off-by: Jerome Glisse <jglisse@redhat.com>
Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Reviewed-by: Thomas Hellstrom <thellstrom@vmware.com>

drivers/gpu/drm/radeon/radeon_ttm.c

@@ -787,7 +787,6 @@ struct ttm_backend *radeon_ttm_backend_create(struct radeon_device *rdev)
 		return NULL;
 	}
 	gtt->backend.bdev = &rdev->mman.bdev;
-	gtt->backend.flags = 0;
 	gtt->backend.func = &radeon_backend_func;
 	gtt->rdev = rdev;
 	gtt->pages = NULL;

include/drm/ttm/ttm_bo_driver.h

@@ -106,7 +106,6 @@ struct ttm_backend_func {
  * struct ttm_backend
  *
  * @bdev: Pointer to a struct ttm_bo_device.
- * @flags: For driver use.
  * @func: Pointer to a struct ttm_backend_func that describes
  * the backend methods.
  *
@@ -114,7 +113,6 @@ struct ttm_backend_func {
 
 struct ttm_backend {
 	struct ttm_bo_device *bdev;
-	uint32_t flags;
 	struct ttm_backend_func *func;
 };