Changing mode on an interface is not allowed if IBSS is disabled for the
current channel.  That restriction should only apply when switching to
the ad-hoc mode, as it was prior to "cfg80211: handle SIOCGIWMODE/SIOCSIWMODE".
Signed-off-by: Pavel Roskin <proski@gnu.org>
Signed-off-by: John W. Linville <linville@tuxdriver.com>