Here is the patch I'm running presently on my snapshot build:
If you wish to test as well, place the patch file here:
package/kernel/mac80211/patches/subsys/982-codel-target.patch
You can confirm the patch is working in your build by checking for "Codel" in your kernel log:
root@AP:~# dmesg | grep Codel | tail -n5
[135091.555225] Codel target, interval 7812, 78125
[135195.713857] Codel target, interval 7812, 78125
[135196.053848] Codel target, interval 7812, 78125
[135338.425862] Codel target, interval 7812, 78125
[135360.191737] Codel target, interval 7812, 78125