Revert "nl80211: Support ACS offload feature flag and attribute"

This reverts commit d3e84ab8.
Reverting these nl80211 attributes definitions that have not been
approved into upstream Linux kernel.

Change-Id: Id51fc42bb38332f19c3ec33379833088d95e9f4a
Signed-off-by: Peng Xu <pxu@codeaurora.org>