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>
diff --git a/drivers/net/wireless/intel/iwlwifi/mvm/debugfs-vif.c b/drivers/net/wireless/intel/iwlwifi/mvm/debugfs-vif.c
index 3a279d3..fb96bc0 100644
--- a/drivers/net/wireless/intel/iwlwifi/mvm/debugfs-vif.c
+++ b/drivers/net/wireless/intel/iwlwifi/mvm/debugfs-vif.c
@@ -724,9 +724,9 @@
 
 		ret = kstrtou32(data, 10, &value);
 		if (ret == 0 && value) {
-			enum ieee80211_band band = (cmd->channel_num <= 14) ?
-						   IEEE80211_BAND_2GHZ :
-						   IEEE80211_BAND_5GHZ;
+			enum nl80211_band band = (cmd->channel_num <= 14) ?
+						   NL80211_BAND_2GHZ :
+						   NL80211_BAND_5GHZ;
 			struct ieee80211_channel chn = {
 				.band = band,
 				.center_freq = ieee80211_channel_to_frequency(