libblkid: exfat: fix fail to find volume label

libblkid: exfat: fix fail to find volume label

Commit f98b56326 set the maximum number of iterations to 10000.
If the volume label is after the 10000th entry, the volume label
will not be found. So this commit sets the maximum number of
iterations to correct value 256×1024×1024/32.

Fixes: f98b56326 ("libblkid: [exfat] Limit maximum number of iterations in find_label")
Signed-off-by: Yuezhang Mo <Yuezhang.Mo@sony.com>
Reviewed-by: Andy Wu <Andy.Wu@sony.com>
Reviewed-by: Aoyama Wataru <wataru.aoyama@sony.com>