sch_htb: fix doc warning in htb_charge_class()

Add description for parameters of htb_charge_class()
to fix gcc W=1 warnings:

net/sched/sch_htb.c:663: warning: Function parameter or member 'q' not described in 'htb_charge_class'
net/sched/sch_htb.c:663: warning: Function parameter or member 'cl' not described in 'htb_charge_class'
net/sched/sch_htb.c:663: warning: Function parameter or member 'level' not described in 'htb_charge_class'
net/sched/sch_htb.c:663: warning: Function parameter or member 'skb' not described in 'htb_charge_class'

Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/sched/sch_htb.c

@@ -675,6 +675,10 @@ static inline void htb_accnt_ctokens(struct htb_class *cl, int bytes, s64 diff)
 
 /**
  * htb_charge_class - charges amount "bytes" to leaf and ancestors
+ * @q: the priority event queue
+ * @cl: the class to start iterate
+ * @level: the minimum level to account
+ * @skb: the socket buffer
  *
  * Routine assumes that packet "bytes" long was dequeued from leaf cl
  * borrowing from "level". It accounts bytes to ceil leaky bucket for