mac80211: backport upstream fix for CSA in IBSS mode

Allows to change channels on-the-fly using CSA when using IBSS.

Signed-off-by: Koen Vandeputte <koen.vandeputte@ncentric.com>

package/kernel/mac80211/patches/320-mac80211-fix-CSA-in-IBSS-mode.patch

@@ -0,0 +1,34 @@
+From: Koen Vandeputte <koen.vandeputte@ncentric.com>
+Date: Wed, 8 Feb 2017 15:29:45 +0100
+Subject: [PATCH] mac80211: fix CSA in IBSS mode
+MIME-Version: 1.0
+Content-Type: text/plain; charset=UTF-8
+Content-Transfer-Encoding: 8bit
+
+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.
+
+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>
+---
+
+--- a/net/mac80211/ibss.c
++++ b/net/mac80211/ibss.c
+@@ -487,14 +487,14 @@ int ieee80211_ibss_csa_beacon(struct iee
+ 	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,