sched: act: ife: migrate to use per-cpu counters

This patch migrates the current counter handling which is protected by a
spinlock to a per-cpu counter handling. This reduce the time where the
spinlock is being held.

Signed-off-by: Alexander Aring <aring@mojatatu.com>
Acked-by: Jamal Hadi Salim <jhs@mojatatu.com>
Signed-off-by: David S. Miller <davem@davemloft.net>