ntfs3: Remove check for PageError

If read_mapping_page() encounters an error, it returns an errno, not a
page with PageError set, so this is dead code.
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>

fs/ntfs3/ntfs_fs.h

@@ -896,13 +896,8 @@ static inline struct page *ntfs_map_page(struct address_space *mapping,
 {
 	struct page *page = read_mapping_page(mapping, index, NULL);
 
-	if (!IS_ERR(page)) {
+	if (!IS_ERR(page))
 		kmap(page);
-		if (!PageError(page))
-			return page;
-		ntfs_unmap_page(page);
-		return ERR_PTR(-EIO);
-	}
 	return page;
 }