AA: mac80211: merge ath9k fixes from bb

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

git-svn-id: svn://svn.openwrt.org/openwrt/branches/attitude_adjustment@42647 3c298f89-4303-0410-b956-a3cf2f4a3e73
Merge remote-tracking branch 'upstream/master'