drm/ttm: stop exporting ttm_mem_io_* functions

Those are not supposed to be used by drivers.
Signed-off-by: Christian König <christian.koenig@amd.com>
Acked-by: Gerd Hoffmann <kraxel@redhat.com>
Link: https://patchwork.freedesktop.org/patch/333290/

drivers/gpu/drm/ttm/ttm_bo_util.c

@@ -102,7 +102,6 @@ int ttm_mem_io_lock(struct ttm_mem_type_manager *man, bool interruptible)
 	mutex_lock(&man->io_reserve_mutex);
 	return 0;
 }
-EXPORT_SYMBOL(ttm_mem_io_lock);
 
 void ttm_mem_io_unlock(struct ttm_mem_type_manager *man)
 {
@@ -111,7 +110,6 @@ void ttm_mem_io_unlock(struct ttm_mem_type_manager *man)
 
 	mutex_unlock(&man->io_reserve_mutex);
 }
-EXPORT_SYMBOL(ttm_mem_io_unlock);
 
 static int ttm_mem_io_evict(struct ttm_mem_type_manager *man)
 {
@@ -153,7 +151,6 @@ int ttm_mem_io_reserve(struct ttm_bo_device *bdev,
 	}
 	return ret;
 }
-EXPORT_SYMBOL(ttm_mem_io_reserve);
 
 void ttm_mem_io_free(struct ttm_bo_device *bdev,
 		     struct ttm_mem_reg *mem)
@@ -169,7 +166,6 @@ void ttm_mem_io_free(struct ttm_bo_device *bdev,
 		bdev->driver->io_mem_free(bdev, mem);
 
 }
-EXPORT_SYMBOL(ttm_mem_io_free);
 
 int ttm_mem_io_reserve_vm(struct ttm_buffer_object *bo)
 {