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/mediatek/mt7601u/init.c

@@ -469,7 +469,7 @@ struct mt7601u_dev *mt7601u_alloc_device(struct device *pdev)
 }
 
 #define CHAN2G(_idx, _freq) {			\
-	.band = IEEE80211_BAND_2GHZ,		\
+	.band = NL80211_BAND_2GHZ,		\
 	.center_freq = (_freq),			\
 	.hw_value = (_idx),			\
 	.max_power = 30,			\
@@ -563,7 +563,7 @@ mt76_init_sband_2g(struct mt7601u_dev *dev)
 {
 	dev->sband_2g = devm_kzalloc(dev->dev, sizeof(*dev->sband_2g),
 				     GFP_KERNEL);
-	dev->hw->wiphy->bands[IEEE80211_BAND_2GHZ] = dev->sband_2g;
+	dev->hw->wiphy->bands[NL80211_BAND_2GHZ] = dev->sband_2g;
 
 	WARN_ON(dev->ee->reg.start - 1 + dev->ee->reg.num >
 		ARRAY_SIZE(mt76_channels_2ghz));