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

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: be034baba83e ("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>