cfg80211: remove enum ieee80211_band

This enum is already perfectly aliased to enum nl80211_band, and
the only reason for it is that we get IEEE80211_NUM_BANDS out of
it. There's no really good reason to not declare the number of
bands in nl80211 though, so do that and remove the cfg80211 one.

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

net/wireless/chan.c

@@ -768,7 +768,7 @@ static bool cfg80211_ir_permissive_chan(struct wiphy *wiphy,
 		if (chan == other_chan)
 			return true;
 
-		if (chan->band != IEEE80211_BAND_5GHZ)
+		if (chan->band != NL80211_BAND_5GHZ)
 			continue;
 
 		r1 = cfg80211_get_unii(chan->center_freq);