net/mlx5: Fix vport QoS cleanup on error

When enabling vport QoS fails, the scheduling node was never freed,
causing a leak.

Add the missing free and reset the vport scheduling node pointer to
NULL.

Fixes: be034ba ("net/mlx5: Make vport QoS enablement more flexible for future extensions")
Signed-off-by: Carolina Jubran <cjubran@nvidia.com>
Reviewed-by: Cosmin Ratiu <cratiu@nvidia.com>
Reviewed-by: Dragos Tatulea <dtatulea@nvidia.com>
Signed-off-by: Tariq Toukan <tariqt@nvidia.com>
Link: https://patch.msgid.link/20250225072608.526866-2-tariqt@nvidia.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

Author: cjubran

drivers/net/ethernet/mellanox/mlx5/core/esw/qos.c

@@ -591,8 +591,11 @@ static int mlx5_esw_qos_vport_enable(struct mlx5_vport *vport, enum sched_node_t
 	sched_node->vport = vport;
 	vport->qos.sched_node = sched_node;
 	err = esw_qos_vport_enable(vport, parent, extack);
-	if (err)
+	if (err) {
+		__esw_qos_free_node(sched_node);
 		esw_qos_put(esw);
+		vport->qos.sched_node = NULL;
+	}
 
 	return err;
 }