Russell King points out that seville_vsc9953 populates
felix->info->num_tx_queues = 8, but this doesn't make it all the way
into ds->num_tx_queues (which is how the user interface netdev queues
get allocated) [1].

[1]: https://lore.kernel.org/all/20240415160150.yejcazpjqvn7vhxu@skbuf/

When num_tx_queues=0 for seville, this is implicitly converted to 1 by
dsa_user_create(), and this is good enough for basic operation for a
switch port. The tc qdisc offload layer works with netdev TX queues,
so for QoS offload we need to pretend we have multiple TX queues. The
VSC9953, like ocelot_ext, doesn't export QoS offload, so it doesn't
really matter. But we can definitely set num_tx_queues=8 for all
switches.

The felix->info->num_tx_queues construct itself seems unnecessary.
It was introduced by commit de143c0e ("net: dsa: felix: Configure
Time-Aware Scheduler via taprio offload") at a time when vsc9959
(LS1028A) was the only switch supported by the driver.

8 traffic classes, and 1 queue per traffic class, is a common
architectural feature of all switches in the family. So they could
all just set OCELOT_NUM_TC and be fine.
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: Colin Foster <colin.foster@in-advantage.com>
Tested-by: Colin Foster <colin.foster@in-advantage.com>
Signed-off-by: David S. Miller <davem@davemloft.net>