ath9k: enable DFS for IBSS mode

Signed-off-by: Simon Wunderlich <siwu@hrz.tu-chemnitz.de>
Signed-off-by: Mathias Kretschmer <mathias.kretschmer@fokus.fraunhofer.de>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

drivers/net/wireless/ath/ath9k/init.c

@@ -845,7 +845,8 @@ static const struct ieee80211_iface_limit if_limits[] = {
 };
 
 static const struct ieee80211_iface_limit if_dfs_limits[] = {
-	{ .max = 1,	.types = BIT(NL80211_IFTYPE_AP) },
+	{ .max = 1,	.types = BIT(NL80211_IFTYPE_AP) |
+				 BIT(NL80211_IFTYPE_ADHOC) },
 };
 
 static const struct ieee80211_iface_combination if_comb[] = {