mac80211: suppress unchanged "limiting TX power" messages

When the AP is advertising limited TX power, the message can be
printed over and over again. Suppress it when the power level
isn't changing.

This fixes https://bugzilla.kernel.org/show_bug.cgi?id=106011

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

net/mac80211/mlme.c

@@ -1379,21 +1379,26 @@ static u32 ieee80211_handle_pwr_constr(struct ieee80211_sub_if_data *sdata,
 	 */
 	if (has_80211h_pwr &&
 	    (!has_cisco_pwr || pwr_level_80211h <= pwr_level_cisco)) {
+		new_ap_level = pwr_level_80211h;
+
+		if (sdata->ap_power_level == new_ap_level)
+			return 0;
+
 		sdata_dbg(sdata,
 			  "Limiting TX power to %d (%d - %d) dBm as advertised by %pM\n",
 			  pwr_level_80211h, chan_pwr, pwr_reduction_80211h,
 			  sdata->u.mgd.bssid);
-		new_ap_level = pwr_level_80211h;
 	} else {  /* has_cisco_pwr is always true here. */
+		new_ap_level = pwr_level_cisco;
+
+		if (sdata->ap_power_level == new_ap_level)
+			return 0;
+
 		sdata_dbg(sdata,
 			  "Limiting TX power to %d dBm as advertised by %pM\n",
 			  pwr_level_cisco, sdata->u.mgd.bssid);
-		new_ap_level = pwr_level_cisco;
 	}
 
-	if (sdata->ap_power_level == new_ap_level)
-		return 0;
-
 	sdata->ap_power_level = new_ap_level;
 	if (__ieee80211_recalc_txpower(sdata))
 		return BSS_CHANGED_TXPOWER;