The only packages we use from this repo are haveged and (now) fastd and its
dependencies, so we can make the switch safely without updating OpenWrt itself
to Barrier Breaker yet.
This updates OpenWRT and rebases our patches.
Furthermore, the mac80211 module is removed as currently the Attitude Adjustment
main repo has a newer version (and some fixes that aren't in the backport repo).
Also, update odhcp6c from Barrier Breaker.