mac80211: fix CSA in IBSS mode

Add the missing IBSS capability flag during capability init as it needs
to be inserted into the generated beacon in order for CSA to work.

Fixes: cd7760e62c2ac ("mac80211: add support for CSA in IBSS mode")
Signed-off-by: Piotr Gawlowicz <gawlowicz@tkn.tu-berlin.de>
Signed-off-by: Mikołaj Chwalisz <chwalisz@tkn.tu-berlin.de>
Tested-by: Koen Vandeputte <koen.vandeputte@ncentric.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

net/mac80211/ibss.c

@@ -487,14 +487,14 @@ int ieee80211_ibss_csa_beacon(struct ieee80211_sub_if_data *sdata,
 	struct beacon_data *presp, *old_presp;
 	struct cfg80211_bss *cbss;
 	const struct cfg80211_bss_ies *ies;
-	u16 capability = 0;
+	u16 capability = WLAN_CAPABILITY_IBSS;
 	u64 tsf;
 	int ret = 0;
 
 	sdata_assert_lock(sdata);
 
 	if (ifibss->privacy)
-		capability = WLAN_CAPABILITY_PRIVACY;
+		capability |= WLAN_CAPABILITY_PRIVACY;
 
 	cbss = cfg80211_get_bss(sdata->local->hw.wiphy, ifibss->chandef.chan,
 				ifibss->bssid, ifibss->ssid,