Melzi boards use melzi pins

Marlin/src/pins/pins_MELZI.h

  * Melzi pin assignments
  */
 
-#define BOARD_NAME "Melzi"
+#ifndef BOARD_NAME
+  #define BOARD_NAME "Melzi"
+#endif
+
 #define IS_MELZI
 #include "pins_SANGUINOLOLU_12.h"

Marlin/src/pins/pins_MELZI_CREALITY.h

  */
 
 #define BOARD_NAME "Melzi (Creality)"
-#define IS_MELZI
 
-#include "pins_SANGUINOLOLU_12.h"
+#include "pins_MELZI.h"
 
 // For the stock CR-10 use the REPRAP_DISCOUNT_FULL_GRAPHIC_SMART_CONTROLLER
 //   option for the display in Configuration.h

Marlin/src/pins/pins_MELZI_MAKR3D.h

  */
 
 #define BOARD_NAME "Melzi (ATmega1284)"
-#define IS_MELZI
-#include "pins_SANGUINOLOLU_12.h"
+#include "pins_MELZI.h"

Marlin/src/pins/pins_MELZI_MALYAN.h

  */
 
 #define BOARD_NAME "Melzi (Malyan)"
-#define IS_MELZI
-
-#include "pins_SANGUINOLOLU_12.h"
+#include "pins_MELZI.h"
 
 #undef LCD_SDSS
 #undef LCD_PINS_RS