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/core.h b/net/wireless/core.h
index 1d3d241..9348a47 100644
--- a/net/wireless/core.h
+++ b/net/wireless/core.h
@@ -444,9 +444,8 @@
 struct ieee80211_channel *
 rdev_freq_to_chan(struct cfg80211_registered_device *rdev,
 		  int freq, enum nl80211_channel_type channel_type);
-int cfg80211_set_freq(struct cfg80211_registered_device *rdev,
-		      struct wireless_dev *wdev, int freq,
-		      enum nl80211_channel_type channel_type);
+int cfg80211_set_monitor_channel(struct cfg80211_registered_device *rdev,
+				 int freq, enum nl80211_channel_type chantype);
 
 int ieee80211_get_ratemask(struct ieee80211_supported_band *sband,
 			   const u8 *rates, unsigned int n_rates,