QUERY_DEV_CAP_VL_PORT_OFFSET
MLX4_GET(field, outbox, QUERY_DEV_CAP_VL_PORT_OFFSET);
MLX4_GET(field, outbox->buf, QUERY_DEV_CAP_VL_PORT_OFFSET);
MLX4_PUT(outbox->buf, field, QUERY_DEV_CAP_VL_PORT_OFFSET);
MLX4_GET(field, outbox, QUERY_DEV_CAP_VL_PORT_OFFSET);