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>

drivers/net/wireless/ath/ath.h

@@ -185,7 +185,7 @@ struct ath_common {
 	bool bt_ant_diversity;
 
 	int last_rssi;
-	struct ieee80211_supported_band sbands[IEEE80211_NUM_BANDS];
+	struct ieee80211_supported_band sbands[NUM_NL80211_BANDS];
 };
 
 static inline const struct ath_ps_ops *ath_ps_ops(struct ath_common *common)