f2fs: change get_new_data_page to pass a locked node page

This patch is for passing a locked node page to get_dnode_of_data.

Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>
diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
index 1cae864..b8e34db 100644
--- a/fs/f2fs/file.c
+++ b/fs/f2fs/file.c
@@ -387,7 +387,7 @@
 	f2fs_balance_fs(sbi);
 
 	ilock = mutex_lock_op(sbi);
-	page = get_new_data_page(inode, index, false);
+	page = get_new_data_page(inode, NULL, index, false);
 	mutex_unlock_op(sbi, ilock);
 
 	if (!IS_ERR(page)) {