net/sched: sch_cake: Add cake_mq qdisc for using cake on mq devices

net/sched: sch_cake: Add cake_mq qdisc for using cake on mq devices

Add a cake_mq qdisc which installs cake instances on each hardware
queue on a multi-queue device.

This is just a copy of sch_mq that installs cake instead of the default
qdisc on each queue. Subsequent commits will add sharing of the config
between cake instances, as well as a multi-queue aware shaper algorithm.

Reviewed-by: Willem de Bruijn <willemb@google.com>
Signed-off-by: Toke Høiland-Jørgensen <toke@redhat.com>
Link: https://patch.msgid.link/20260109-mq-cake-sub-qdisc-v8-3-8d613fece5d8@redhat.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>