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

net/sched/sch_htb.c:380: warning: Function parameter or member 'q' not described in 'htb_remove_class_from_row'
net/sched/sch_htb.c:380: warning: Function parameter or member 'cl' not described in 'htb_remove_class_from_row'
net/sched/sch_htb.c:380: warning: Function parameter or member 'mask' not described in 'htb_remove_class_from_row'
Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>