drm/ttm: Remove ttm_bo_reference and ttm_bo_unref

Both functions are obsolete and all calls have been replaced by
ttm_bo_get and ttm_bo_put.

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Christian König <christian.koenig@amd.com>
Reviewed-by: Huang Rui <ray.huang@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

include/drm/ttm/ttm_bo_api.h

@@ -295,23 +295,6 @@ static inline void ttm_bo_get(struct ttm_buffer_object *bo)
 	kref_get(&bo->kref);
 }
 
-/**
- * ttm_bo_reference - reference a struct ttm_buffer_object
- *
- * @bo: The buffer object.
- *
- * Returns a refcounted pointer to a buffer object.
- *
- * This function is deprecated. Use @ttm_bo_get instead.
- */
-
-static inline struct ttm_buffer_object *
-ttm_bo_reference(struct ttm_buffer_object *bo)
-{
-	ttm_bo_get(bo);
-	return bo;
-}
-
 /**
  * ttm_bo_get_unless_zero - reference a struct ttm_buffer_object unless
  * its refcount has already reached zero.
@@ -386,17 +369,6 @@ int ttm_bo_validate(struct ttm_buffer_object *bo,
  */
 void ttm_bo_put(struct ttm_buffer_object *bo);
 
-/**
- * ttm_bo_unref
- *
- * @bo: The buffer object.
- *
- * Unreference and clear a pointer to a buffer object.
- *
- * This function is deprecated. Use @ttm_bo_put instead.
- */
-void ttm_bo_unref(struct ttm_buffer_object **bo);
-
 /**
  * ttm_bo_add_to_lru
  *