Move duplicated mapgen parameters to class MapgenBasic (#9134)

'large_cave_depth', 'dungeon_ymin' and 'dungeon_ymax' are duplicated across many mapgens so should have been in class MapgenBasic from the start.

src/mapgen/mapgen.h

@@ -285,4 +285,7 @@ protected:
 	int large_cave_num_min;
 	int large_cave_num_max;
 	float large_cave_flooded;
+	s16 large_cave_depth;
+	s16 dungeon_ymin;
+	s16 dungeon_ymax;
 };

src/mapgen/mapgen_carpathian.h

@@ -93,10 +93,6 @@ private:
 	float river_depth;
 	float valley_width;
 
-	s16 large_cave_depth;
-	s16 dungeon_ymin;
-	s16 dungeon_ymax;
-
 	Noise *noise_height1;
 	Noise *noise_height2;
 	Noise *noise_height3;

src/mapgen/mapgen_flat.h

@@ -75,13 +75,10 @@ public:
 
 private:
 	s16 ground_level;
-	s16 large_cave_depth;
 	float lake_threshold;
 	float lake_steepness;
 	float hill_threshold;
 	float hill_steepness;
-	s16 dungeon_ymin;
-	s16 dungeon_ymax;
 
 	Noise *noise_terrain;
 };

src/mapgen/mapgen_fractal.h

@@ -85,10 +85,6 @@ public:
 private:
 	u16 formula;
 	bool julia;
-
-	s16 large_cave_depth;
-	s16 dungeon_ymin;
-	s16 dungeon_ymax;
 	u16 fractal;
 	u16 iterations;
 	v3f scale;

src/mapgen/mapgen_v5.h

@@ -74,10 +74,6 @@ public:
 	int generateBaseTerrain();
 
 private:
-	s16 large_cave_depth;
-	s16 dungeon_ymin;
-	s16 dungeon_ymax;
-
 	Noise *noise_factor;
 	Noise *noise_height;
 	Noise *noise_ground;

src/mapgen/mapgen_v7.h

@@ -108,10 +108,6 @@ private:
 	s16 floatland_level;
 	s16 shadow_limit;
 
-	s16 large_cave_depth;
-	s16 dungeon_ymin;
-	s16 dungeon_ymax;
-
 	Noise *noise_terrain_base;
 	Noise *noise_terrain_alt;
 	Noise *noise_terrain_persist;

src/mapgen/mapgen_valleys.h

@@ -100,10 +100,6 @@ private:
 	float river_depth_bed;
 	float river_size_factor;
 
-	s16 large_cave_depth;
-	s16 dungeon_ymin;
-	s16 dungeon_ymax;
-
 	Noise *noise_inter_valley_fill;
 	Noise *noise_inter_valley_slope;
 	Noise *noise_rivers;