Revert "pkt_sched: sch_sfq: dump a real number of flows"

This reverts commit f867e6af.

Based upon discussions between Jarek and Patrick McHardy
this is field being set is more a config parameter than a
statistic.  And we should add a true statistic to provide
this information if we really want it.

Signed-off-by: David S. Miller <davem@davemloft.net>