net_sched: copy exts->type in tcf_exts_change()

We need to copy exts->type when committing the change, otherwise
it would be always 0. This is a quick fix for -net and -stable,
for net-next tcf_exts will be removed.

Fixes: commit 33be6271

 ("net_sched: act: use standard struct list_head")
Reported-by: Jamal Hadi Salim <jhs@mojatatu.com>
Cc: Jamal Hadi Salim <jhs@mojatatu.com>
Cc: John Fastabend <john.fastabend@gmail.com>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Acked-by: Jamal Hadi Salim <jhs@mojatatu.com>
Signed-off-by: David S. Miller <davem@davemloft.net>