mac80211: support secondary channel offset in CSA

Add support for the secondary channel offset IE in channel
switch announcements. This is necessary for proper handling
of CSA on HT access points.

For this to work it is also necessary to convert everything
here to use chandef structs instead of just channels. The
driver updates aren't really correct though. In particular,
the TI wl18xx driver update can't possibly be right since
it just ignores the new channel width for lack of firmware
API.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
diff --git a/net/mac80211/ieee80211_i.h b/net/mac80211/ieee80211_i.h
index 10c3180..8f240c0 100644
--- a/net/mac80211/ieee80211_i.h
+++ b/net/mac80211/ieee80211_i.h
@@ -1019,7 +1019,7 @@
 	enum mac80211_scan_state next_scan_state;
 	struct delayed_work scan_work;
 	struct ieee80211_sub_if_data __rcu *scan_sdata;
-	struct ieee80211_channel *csa_channel;
+	struct cfg80211_chan_def csa_chandef;
 	/* For backward compatibility only -- do not use */
 	struct cfg80211_chan_def _oper_chandef;
 
@@ -1183,6 +1183,7 @@
 	const u8 *pwr_constr_elem;
 	const struct ieee80211_timeout_interval_ie *timeout_int;
 	const u8 *opmode_notif;
+	const struct ieee80211_sec_chan_offs_ie *sec_chan_offs;
 
 	/* length of them, respectively */
 	u8 ssid_len;