ath9k: add initial tx queueing rework patches

This forces all packets (even for un-aggregated traffic) through
software queues to improve fairness and stability

Signed-off-by: Felix Fietkau <nbd@openwrt.org>

Backport of r37483

git-svn-id: svn://svn.openwrt.org/openwrt/branches/attitude_adjustment@37533 3c298f89-4303-0410-b956-a3cf2f4a3e73