Calculate airport noise level in permissive mode as same as lenient

src/station_cmd.cpp

@@ -2580,13 +2580,14 @@ uint8_t GetAirportNoiseLevelForDistance(const AirportSpec *as, uint distance)
 	 * So no need to go any further*/
 	if (as->noise_level < 2) return as->noise_level;
 
-	if (_settings_game.difficulty.town_council_tolerance == TOWN_COUNCIL_PERMISSIVE) return 1;
+	auto tolerance = _settings_game.difficulty.town_council_tolerance;
+	if (tolerance == TOWN_COUNCIL_PERMISSIVE) tolerance = TOWN_COUNCIL_LENIENT;
 
 	/* The steps for measuring noise reduction are based on the "magical" (and arbitrary) 8 base distance
 	 * adding the town_council_tolerance 4 times, as a way to graduate, depending of the tolerance.
 	 * Basically, it says that the less tolerant a town is, the bigger the distance before
 	 * an actual decrease can be granted */
-	uint8_t town_tolerance_distance = 8 + (_settings_game.difficulty.town_council_tolerance * 4);
+	uint8_t town_tolerance_distance = 8 + (tolerance * 4);
 
 	/* now, we want to have the distance segmented using the distance judged bareable by town
 	 * This will give us the coefficient of reduction the distance provides. */