sch_htb: Fail on unsupported parameters when offload is requested

sch_htb: Fail on unsupported parameters when offload is requested

The current implementation of HTB offload doesn't support some
parameters. Instead of ignoring them, actively return the EINVAL error
when they are set to non-defaults.

As this patch goes to stable, the driver API is not changed here. If
future drivers support more offload parameters, the checks can be moved
to the driver side.

Note that the buffer and cbuffer parameters are also not supported, but
the tc userspace tool assigns some default values derived from rate and
ceil, and identifying these defaults in sch_htb would be unreliable, so
they are still ignored.

Fixes: d03b195b5aa0 ("sch_htb: Hierarchical QoS hardware offload")
Reported-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Maxim Mikityanskiy <maximmi@nvidia.com>
Reviewed-by: Tariq Toukan <tariqt@nvidia.com>
Link: https://lore.kernel.org/r/20220125100654.424570-1-maximmi@nvidia.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>