Remove orphaned prototype

Rajeev rastogi

Author: bmomjian

src/include/access/gin_private.h

@@ -697,7 +697,6 @@ extern int GinDataLeafPageGetItemsToTbm(Page page, TIDBitmap *tbm);
 extern BlockNumber createPostingTree(Relation index,
 				  ItemPointerData *items, uint32 nitems,
 				  GinStatsData *buildStats);
-extern void GinDataPageAddItemPointer(Page page, ItemPointer data, OffsetNumber offset);
 extern void GinDataPageAddPostingItem(Page page, PostingItem *data, OffsetNumber offset);
 extern void GinPageDeletePostingItem(Page page, OffsetNumber offset);
 extern void ginInsertItemPointers(Relation index, BlockNumber rootBlkno,