mac80211: extend fast-xmit to cover IBSS

IBSS can be supported very easily since it uses the standard station
authorization state etc. so it just needs to be covered by the header
building switch statement.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>

net/mac80211/tx.c

@@ -2466,6 +2466,13 @@ void ieee80211_check_fast_xmit(struct sta_info *sta)
 	fc = cpu_to_le16(IEEE80211_FTYPE_DATA | IEEE80211_STYPE_DATA);
 
 	switch (sdata->vif.type) {
+	case NL80211_IFTYPE_ADHOC:
+		/* DA SA BSSID */
+		build.da_offs = offsetof(struct ieee80211_hdr, addr1);
+		build.sa_offs = offsetof(struct ieee80211_hdr, addr2);
+		memcpy(hdr->addr3, sdata->u.ibss.bssid, ETH_ALEN);
+		build.hdr_len = 24;
+		break;
 	case NL80211_IFTYPE_STATION:
 		if (test_sta_flag(sta, WLAN_STA_TDLS_PEER)) {
 			/* DA SA BSSID */