sch_hhf: ensure quantum and hhf_non_hh_weight are non-zero

commit d4d6ec6d upstream.

In case of TCA_HHF_NON_HH_WEIGHT or TCA_HHF_QUANTUM is zero,
it would make no progress inside the loop in hhf_dequeue() thus
kernel would get stuck.

Fix this by checking this corner case in hhf_change().

Fixes: 10239edf

 ("net-qdisc-hhf: Heavy-Hitter Filter (HHF) qdisc")
Reported-by:  <syzbot+bc6297c11f19ee807dc2@syzkaller.appspotmail.com>
Reported-by:  <syzbot+041483004a7f45f1f20a@syzkaller.appspotmail.com>
Reported-by:  <syzbot+55be5f513bed37fc4367@syzkaller.appspotmail.com>
Cc: Jamal Hadi Salim <jhs@mojatatu.com>
Cc: Jiri Pirko <jiri@resnulli.us>
Cc: Terry Lam <vtlam@google.com>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>