net/mlx5: qos: Refactor locking to a qos domain mutex

E-Switch qos changes used the esw state_lock to serialize qos changes.
With the introduction of cross-esw scheduling, multiple E-Switches might
be involved in a qos operation, so prepare for that by switching locking
to use a qos domain mutex.
Add three helper functions:
- esw_qos_lock
- esw_qos_unlock
- esw_assert_qos_lock_held

Convert existing direct lock/unlock/lockdep calls to them. Also call
esw_assert_qos_lock_held in a couple more places.

mlx5_esw_qos_set_vport_rate expected to be called with the esw
state_lock already held.
Change it to instead acquire the qos lock directly.

mlx5_eswitch_get_vport_config also accessed qos properties with the esw
state lock. Introduce a new function mlx5_esw_qos_get_vport_rate to
access those with the correct lock and change get_vport_config to use
it.

Finally, mlx5_vport_disable is called from the cleanup path with the esw
state_lock held, so have it additionally acquire the qos lock to make
sure there are no races.

Signed-off-by: Cosmin Ratiu <cratiu@nvidia.com>
Signed-off-by: Tariq Toukan <tariqt@nvidia.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>