pc-bios/s390: update images

Contains the following commits:
- s390: Do not pass inofficial IPL type to the guest

For s390-netboot.img, this also contains the following commits (update
was forgotten last time):
- pc-bios/s390-ccw: Move string arrays from bootmap header to .c file
- pc-bios/s390-ccw: Increase virtio timeout to 30 seconds

Signed-off-by: Cornelia Huck <cohuck@redhat.com>