net/mlx5: Add traffic class scheduling support for vport QoS

Introduce support for traffic class (TC) scheduling on vports by
allowing the vport to own multiple TC scheduling nodes. This patch
enables more granular control of QoS by defining three distinct QoS
states for vports, each providing unique scheduling behavior:

1. Regular QoS: The `sched_node` represents the vport directly,
   handling QoS as a single scheduling entity.
2. TC QoS on the vport: The `sched_node` acts as a TC arbiter, enabling
   TC scheduling directly on the vport.
3. TC QoS on the parent node: The `sched_node` functions as a rate
   limiter, with TC arbitration enabled at the parent level, associating
   multiple scheduling nodes with each vport.

Key changes include:

- Added support for new scheduling elements, vport traffic class and
  rate limiter.

- New helper functions for creating, destroying, and restoring vport TC
  scheduling nodes, handling transitions between regular QoS and TC
  arbitration states.

- Updated `esw_qos_vport_enable()` and `esw_qos_vport_disable()` to
  support both regular QoS and TC arbitration states, ensuring consistent
  transitions between scheduling modes.

- Introduced a `sched_nodes` array under `vport->qos` to store multiple
  TC scheduling nodes per vport, enabling finer control over per-TC QoS.

- Enhanced `esw_qos_vport_update_parent()` to handle transitions between
  the three QoS states based on the current and new parent node types.

This patch lays the groundwork for future support for configuring tc-bw
on vports. Although the infrastructure is in place, full support for
tc-bw is not yet implemented; attempts to set tc-bw on vports will
return `-EOPNOTSUPP`.

No functional changes are introduced at this stage.

Signed-off-by: Carolina Jubran <cjubran@nvidia.com>
Reviewed-by: Cosmin Ratiu <cratiu@nvidia.com>
Signed-off-by: Tariq Toukan <tariqt@nvidia.com>
Signed-off-by: Mark Bloch <mbloch@nvidia.com>
Link: https://patch.msgid.link/20250629142138.361537-7-mbloch@nvidia.com


Signed-off-by: Jakub Kicinski <kuba@kernel.org>