selftests/tc-testing: Remove configs that no longer exist

Some qdiscs and classifiers have recently been retired from kernel.
However, tc-testing config is still cluttered with them which causes noise
when using merge_config.sh script to update existing config for tc-testing
compatibility. Remove the config settings for affected qdiscs and
classifiers.

Fixes: fb38306c ("net/sched: Retire ATM qdisc")
Fixes: 051d4420 ("net/sched: Retire CBQ qdisc")
Fixes: bbe77c14 ("net/sched: Retire dsmark qdisc")
Fixes: 265b4da8 ("net/sched: Retire rsvp classifier")
Fixes: 8c710f75

 ("net/sched: Retire tcindex classifier")
Signed-off-by: Vlad Buslov <vladbu@nvidia.com>
Reviewed-by: Pedro Tammela <pctammela@mojatatu.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>