ife: error out when nla attributes are empty

act_ife at least requires TCA_IFE_PARMS, so we have to bail out
when there is no attribute passed in.

Reported-by:  <syzbot+fbb5b288c9cb6a2eeac4@syzkaller.appspotmail.com>
Fixes: ef6980b6 ("introduce IFE action")
Cc: Jamal Hadi Salim <jhs@mojatatu.com>
Cc: Jiri Pirko <jiri@resnulli.us>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>