exfat: fix wrong hint_stat initialization in exfat_find_dir_entry()

We found the wrong hint_stat initialization in exfat_find_dir_entry().
It should be initialized when cluster is EXFAT_EOF_CLUSTER.

Fixes: ca061973 ("exfat: add directory operations")
Cc: stable@vger.kernel.org # v5.7
Reviewed-by: Sungjong Seo <sj1557.seo@samsung.com>
Signed-off-by: Namjae Jeon <namjae.jeon@samsung.com>