f2fs: remove unnecessary f2fs_put_page in f2fs_rename

[1] changed the below condition, which made f2fs_put_page() voided.
This patch reapplies the AL's resolution in -next from [2].

-       if (S_ISDIR(old_inode->i_mode)) {
+       if (old_is_dir && old_dir != new_dir) {
                old_dir_entry = f2fs_parent_dir(old_inode, &old_dir_page);
                if (!old_dir_entry) {
                        if (IS_ERR(old_dir_page))

[1] 7deee77b

 ("f2fs: Avoid reading renamed directory if parent does not change")
[2] https://lore.kernel.org/all/20231220013402.GW1674809@ZenIV/

Suggested-by: Al Viro <viro@zeniv.linux.org.uk>
Reviewed-by: Chao Yu <chao@kernel.org>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>