sched: add missing curly braces in else branch in tc_ctl_tfilter

Curly braces need to be there, for stylistic reasons.

Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Acked-by: Jamal Hadi Salim <jhs@mojatatu.com>
Signed-off-by: David S. Miller <davem@davemloft.net>