Merge branch 's390-for-upstream' of git://github.com/agraf/qemu

* 's390-for-upstream' of git://github.com/agraf/qemu:
  s390: update s390-ccw.img
  S390: BIOS boot from given device
  S390: Add virtio-blk boot
  S390: Merging s390_ipl_cpu and s390_ipl_reset
  S390: BIOS create link to src folder for .img file
  S390: BIOS check for file