IB/mlx5: Add necessary delay drop assignment

Assign the statistics and configuration structure pointer on success.

Fixes: fe248c3a ('IB/mlx5: Add delay drop configuration and statistics')
Signed-off-by: Maor Gottlieb <maorg@mellanox.com>
Signed-off-by: Leon Romanovsky <leon@kernel.org>
Signed-off-by: Doug Ledford <dledford@redhat.com>

drivers/infiniband/hw/mlx5/main.c

@@ -3793,6 +3793,8 @@ static int delay_drop_debugfs_init(struct mlx5_ib_dev *dev)
 	if (!dbg->timeout_debugfs)
 		goto out_debugfs;
 
+	dev->delay_drop.dbg = dbg;
+
 	return 0;
 
 out_debugfs: