This adds ACS support to hostapd. Currently only survey-based
algorithm is available.
To use ACS you need to enable CONFIG_ACS=y in .config and use
channel=0 (or channel=acs_survey) in hostapd.conf.
For more details see wiki page [1] or comments in src/ap/acs.c.
[1]: http://wireless.kernel.org/en/users/Documentation/acs
Signed-hostap: Michal Kazior <michal.kazior@tieto.com>
