net: sched: choke: remove dead filter classify code

sch_choke is classless qdisc so it does not define cl_ops. Therefore
filter_list cannot be ever changed, being NULL all the time.
Reason is this check in tc_ctl_tfilter:

	/* Is it classful? */
	cops = q->ops->cl_ops;
	if (!cops)
		return -EINVAL;

So remove this dead code.

Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>