exfat: fix incorrect directory checksum after rename to shorter name

exfat: fix incorrect directory checksum after rename to shorter name

When renaming a file in-place to a shorter name, exfat_remove_entries
marks excess entries as DELETED, but es->num_entries is not updated
accordingly. As a result, exfat_update_dir_chksum iterates over the
deleted entries and computes an incorrect checksum.

This does not lead to persistent corruption because mark_inode_dirty()
is called afterward, and __exfat_write_inode later recomputes the
checksum using the correct num_entries value.

Fix by setting es->num_entries = num_entries in exfat_init_ext_entry.

Signed-off-by: Chi Zhiling <chizhiling@kylinos.cn>
Reviewed-by: Sungjong Seo <sj1557.seo@samsung.com>
Reviewed-by: Yuezhang Mo <Yuezhang.Mo@sony.com>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>