nl80211: limit band information in non-split data

In non-split data, we shouldn't be adding S1G and 6 GHz
data (or future bands) since we're really close to the
4k message size limit. Remove those bands, any modern
userspace that can use S1G or 6 GHz should already be
using split dumps, and if not then it needs to update.

Link: https://lore.kernel.org/r/20210712215329.31444162a2c2.I5555312e4a074c84f8b4e7ad79dc4d1fbfc5126c@changeid
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

net/wireless/nl80211.c

@@ -2351,7 +2351,10 @@ static int nl80211_send_wiphy(struct cfg80211_registered_device *rdev,
 			goto nla_put_failure;
 
 		for (band = state->band_start;
-		     band < NUM_NL80211_BANDS; band++) {
+		     band < (state->split ?
+				NUM_NL80211_BANDS :
+				NL80211_BAND_60GHZ + 1);
+		     band++) {
 			struct ieee80211_supported_band *sband;
 
 			/* omit higher bands for ancient software */