selftests: fix flower parent qdisc

Flower tests used to create ingress filter with specified parent qdisc
"parent ffff:" but dump them on "ingress". With recent commit that fixed
tcm_parent handling in dump those are not considered same parent anymore,
which causes iproute2 tc to emit additional "parent ffff:" in first line of
filter dump output. The change in output causes filter match in tests to
fail.

Prevent parent qdisc output when dumping filters in flower tests by always
correctly specifying "ingress" parent both when creating and dumping
filters.

Fixes: a7df4870 ("net_sched: fix tcm_parent in tc filter dump")
Signed-off-by: Vlad Buslov <vladbu@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>