net/mlx5e: QoS, Fix wrongfully setting parent_element_id on MODIFY_SCHEDULING_ELEMENT

According to HW spec parent_element_id field should be reserved (0x0) when calling
MODIFY_SCHEDULING_ELEMENT command.

This patch remove the wrong initialization of reserved field, parent_element_id, on
mlx5_qos_update_node.

Fixes: 214baf22870c ("net/mlx5e: Support HTB offload")
Signed-off-by: Maor Dickman <maord@nvidia.com>
Reviewed-by: Eli Cohen <elic@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>

net/mlx5e: Support HTB offload

This commit adds support for HTB offload in the mlx5e driver.

Performance:

NIC: Mellanox ConnectX-6 Dx
CPU: Intel(R) Xeon(R) CPU E5-2680 v3 @ 2.50GHz (24 cores with HT)

100 Gbit/s line rate, 500 UDP streams @ ~200 Mbit/s each
48 traffic classes, flower used for steering
No shaping (rate limits set to 4 Gbit/s per TC) - checking for max
throughput.

Baseline: 98.7 Gbps, 8.25 Mpps
HTB: 6.7 Gbps, 0.56 Mpps
HTB offload: 95.6 Gbps, 8.00 Mpps

Limitations:

1. 256 leaf nodes, 3 levels of depth.

2. Granularity for ceil is 1 Mbit/s. Rates are converted to weights, and
the bandwidth is split among the siblings according to these weights.
Other parameters for classes are not supported.

Ethtool statistics support for QoS SQs are also added. The counters are
called qos_txN_*, where N is the QoS queue number (starting from 0, the
numeration is separate from the normal SQs), and * is the counter name
(the counters are the same as for the normal SQs).

Signed-off-by: Maxim Mikityanskiy <maximmi@mellanox.com>
Reviewed-by: Tariq Toukan <tariqt@nvidia.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>