Use the ITEM_NONE constant for the registeredItem save block field

src/new_game.c

@@ -44,6 +44,7 @@
 #include "berry_powder.h"
 #include "mystery_gift.h"
 #include "union_room_chat.h"
+#include "constants/items.h"
 
 extern const u8 EventScript_ResetAllMapFlags[];
 
@@ -181,7 +182,7 @@ void NewGameInitData(void)
     ResetPokemonStorageSystem();
     ClearRoamerData();
     ClearRoamerLocationData();
-    gSaveBlock1Ptr->registeredItem = 0;
+    gSaveBlock1Ptr->registeredItem = ITEM_NONE;
     ClearBag();
     NewGameInitPCItems();
     ClearPokeblocks();