gcc: port missing patches from 4.6 to 4.8

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

git-svn-id: svn://svn.openwrt.org/openwrt@36693 3c298f89-4303-0410-b956-a3cf2f4a3e73
gcc: remove version 4.7

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

git-svn-id: svn://svn.openwrt.org/openwrt@36694 3c298f89-4303-0410-b956-a3cf2f4a3e73
ath9k: merge some ar934x stability fixes

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

git-svn-id: svn://svn.openwrt.org/openwrt@36695 3c298f89-4303-0410-b956-a3cf2f4a3e73