f2fs: fix to call clear_page_private_reference in .{release,invalid}_folio

b763f3be ("f2fs: restructure f2fs page.private layout") missed
to call clear_page_private_reference() in .{release,invalid}_folio,
fix it, though it's not a big deal since folio_detach_private() was
called to clear all privae info and reference count in the page.

BTW, remove page_private_reference() definition as it never be used.
Signed-off-by: Chao Yu <chao@kernel.org>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

fs/f2fs/data.c

@@ -3698,6 +3698,7 @@ void f2fs_invalidate_folio(struct folio *folio, size_t offset, size_t length)
 		}
 	}
 
+	clear_page_private_reference(&folio->page);
 	clear_page_private_gcing(&folio->page);
 
 	if (test_opt(sbi, COMPRESS_CACHE) &&
@@ -3723,6 +3724,7 @@ bool f2fs_release_folio(struct folio *folio, gfp_t wait)
 			clear_page_private_data(&folio->page);
 	}
 
+	clear_page_private_reference(&folio->page);
 	clear_page_private_gcing(&folio->page);
 
 	folio_detach_private(folio);

fs/f2fs/f2fs.h

@@ -1448,7 +1448,6 @@ static inline void clear_page_private_##name(struct page *page) \
 }
 
 PAGE_PRIVATE_GET_FUNC(nonpointer, NOT_POINTER);
-PAGE_PRIVATE_GET_FUNC(reference, REF_RESOURCE);
 PAGE_PRIVATE_GET_FUNC(inline, INLINE_INODE);
 PAGE_PRIVATE_GET_FUNC(gcing, ONGOING_MIGRATION);
 PAGE_PRIVATE_GET_FUNC(dummy, DUMMY_WRITE);