pc-bios/s390-ccw: ISO-9660 El Torito boot implementation

pc-bios/s390-ccw: ISO-9660 El Torito boot implementation

This patch enables boot from media formatted according to
ISO-9660 and El Torito bootable CD specification.

We try to boot from device as ISO-9660 media when SCSI IPL failed.

The first boot catalog entry with bootable flag is used.

ISO-9660 media with default 2048-bytes sector size only is supported.

Signed-off-by: Maxim Samoylov <[email protected]>
Reviewed-by: David Hildenbrand <[email protected]>
Signed-off-by: Cornelia Huck <[email protected]>