cfg80211: clarify set_channel APIs

Now that we've removed all uses of the set_channel
API except for the monitor channel and in libertas,
clarify this. Split the libertas mesh use into a
new libertas_set_mesh_channel() operation, just to
keep backward compatibility, and rename the normal
set_channel() to set_monitor_channel().

Also describe the desired set_monitor_channel()
semantics more clearly.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/net/wireless/wext-sme.c b/net/wireless/wext-sme.c
index 7decbd3..1f773f6 100644
--- a/net/wireless/wext-sme.c
+++ b/net/wireless/wext-sme.c
@@ -111,9 +111,15 @@
 
 	wdev->wext.connect.channel = chan;
 
-	/* SSID is not set, we just want to switch channel */
+	/*
+	 * SSID is not set, we just want to switch monitor channel,
+	 * this is really just backward compatibility, if the SSID
+	 * is set then we use the channel to select the BSS to use
+	 * to connect to instead. If we were connected on another
+	 * channel we disconnected above and reconnect below.
+	 */
 	if (chan && !wdev->wext.connect.ssid_len) {
-		err = cfg80211_set_freq(rdev, wdev, freq, NL80211_CHAN_NO_HT);
+		err = cfg80211_set_monitor_channel(rdev, freq, NL80211_CHAN_NO_HT);
 		goto out;
 	}