net: sched: sch_dualpi2: use qdisc_dequeue_drop() for dequeue drops

net: sched: sch_dualpi2: use qdisc_dequeue_drop() for dequeue drops

DualPI2 drops packets during dequeue but was using kfree_skb_reason()
directly, bypassing trace_qdisc_drop. Convert to qdisc_dequeue_drop()
and add QDISC_DROP_L4S_STEP_NON_ECN to the qdisc drop reason enum.

- Set TCQ_F_DEQUEUE_DROPS flag in dualpi2_init()
- Use enum qdisc_drop_reason in drop_and_retry()
- Replace kfree_skb_reason() with qdisc_dequeue_drop()

Signed-off-by: Jesper Dangaard Brouer <hawk@kernel.org>
Reviewed-by: Toke Høiland-Jørgensen <toke@redhat.com>
Link: https://patch.msgid.link/177211351978.3011628.11267023360997620069.stgit@firesoul
Signed-off-by: Jakub Kicinski <kuba@kernel.org>