fs/iso9660: Incorrect check for entry boundary

fs/iso9660: Incorrect check for entry boundary

An SL entry consists of the entry info and the component area.
The entry info should take up 5 bytes instead of sizeof(*entry).
The area after the first 5 bytes is the component area. It is
incorrect to use the sizeof(*entry) to check the entry boundary.

Signed-off-by: Lidong Chen <lidong.chen@oracle.com>
Reviewed-by: Thomas Schmitt <scdbackup@gmx.net>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>