[NET]: Fix sch_api to properly set sch->parent on the root.

Fix sch_api to correctly set sch->parent for both ingress and egress
qdiscs in qdisc_create().

Signed-off-by: Patrick McHardy <trash@kaber.net>
Signed-off-by: Peter P Waskiewicz Jr <peter.p.waskiewicz.jr@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>