iwlagn: fix resume for ADHOC network

 ieee80211_notify_mac only reconnect BSS networks. Since IBSS does
 not need any auth or assoc steps we can just resume to the same
 condition before suspend. This patch will reestablish the ad-hoc
 network once it comes back from resume.

http://www.intellinuxwireless.org/bugzilla/show_bug.cgi?id=1774

Signed-off-by: Mohamed Abbas <mohamed.abbas@intel.com>
Signed-off-by: Reinette Chatre <reinette.chatre@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>