mac80211: debugfs: improve airtime_flags handler readability

Improve airtime_flags debugfs handler readability reporting configured
airtime flags in both numeric and human readable manner

Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
Acked-by: Toke Høiland-Jørgensen <toke@redhat.com>
Link: https://lore.kernel.org/r/9df7e40b45e95bb0b320317831455beaed1ee3ee.1574872357.git.lorenzo@kernel.org


[remove AQL since it's no longer there]
Signed-off-by: Johannes Berg <johannes.berg@intel.com>