ath9k: disable periodic entropy gathering (keep initial) to fix some stability issues

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

git-svn-id: svn://svn.openwrt.org/openwrt/trunk@41952 3c298f89-4303-0410-b956-a3cf2f4a3e73
mac80211: refresh patch

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

git-svn-id: svn://svn.openwrt.org/openwrt/trunk@41953 3c298f89-4303-0410-b956-a3cf2f4a3e73