ath9k: merge another round of cleanups and fixes submitted to linux-wireless

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

git-svn-id: svn://svn.openwrt.org/openwrt/trunk@39054 3c298f89-4303-0410-b956-a3cf2f4a3e73
upgrade 3.12 targets to 3.12.5

Signed-off-by: Imre Kaloz <kaloz@openwrt.org>



git-svn-id: svn://svn.openwrt.org/openwrt/trunk@39055 3c298f89-4303-0410-b956-a3cf2f4a3e73