Unless Adtran has upgraded their firmware, the NV5660 (although the command is there) does not support the NV160 WAP devices.
However, if the feature was enabled, the AC controller build for the NV160 would be built the same in the NV5660 as it is in other Adtran routers.
Thanks for the gponian response! I did manage to find a firmware version that supports the dot11ap access-point-control on the NV5660. With NV5660A-R11-10-6-E.biz I was able to apply the dot11ap access-point-control command and the dot11ap interfaces built no problamo!