CVE-2025-37798 codel: remove sch->q.qlen check before qdisc_tree_reduce_backlog()

In the Linux kernel, the following vulnerability has been resolved: codel: remove sch-q.qlen check before qdisctreereducebacklog After making all -qlennotify callbacks idempotent, now it is safe to remove the check of qlen!=0 from both fqcodeldequeue and codelqdiscdequeue...