f2fs: remove duplicated type casting

Since DUMMY_WRITTEN_PAGE and ATOMIC_WRITTEN_PAGE have already been
converted as unsigned long type, we don't need do type casting again.

Signed-off-by: Xiaojun Wang <wangxiaojun11@huawei.com>
Reported-by: Jack Qiu <jack.qiu@huawei.com>
Reviewed-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
index 6a8c92f..774582a 100644
--- a/fs/f2fs/segment.c
+++ b/fs/f2fs/segment.c
@@ -189,7 +189,7 @@ void f2fs_register_inmem_page(struct inode *inode, struct page *page)
 
 	f2fs_trace_pid(page);
 
-	f2fs_set_page_private(page, (unsigned long)ATOMIC_WRITTEN_PAGE);
+	f2fs_set_page_private(page, ATOMIC_WRITTEN_PAGE);
 
 	new = f2fs_kmem_cache_alloc(inmem_entry_slab, GFP_NOFS);