net/mlx5: Fix QoS reference leak in vport enable error path

Add missing esw_qos_put() call when __esw_qos_alloc_node() fails in
mlx5_esw_qos_vport_enable().

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>
Signed-off-by: Mark Bloch <mbloch@nvidia.com>
Link: https://patch.msgid.link/20250820133209.389065-6-mbloch@nvidia.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

Author: cjubran

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

@@ -1109,8 +1109,10 @@ static int mlx5_esw_qos_vport_enable(struct mlx5_vport *vport, enum sched_node_t
 
 	parent_esw = parent ? parent->esw : esw;
 	sched_node = __esw_qos_alloc_node(parent_esw, 0, type, parent);
-	if (!sched_node)
+	if (!sched_node) {
+		esw_qos_put(esw);
 		return -ENOMEM;
+	}
 	if (!parent)
 		list_add_tail(&sched_node->entry, &esw->qos.domain->nodes);