brcm47xx: add initial support for kernel 3.9


git-svn-id: svn://svn.openwrt.org/openwrt/trunk@36926 3c298f89-4303-0410-b956-a3cf2f4a3e73
brcm47xx: remove support for kernel 3.6


git-svn-id: svn://svn.openwrt.org/openwrt/trunk@36927 3c298f89-4303-0410-b956-a3cf2f4a3e73