Merge tag 'tags/s390x-2018-06-18' into staging

Merge tag 'tags/s390x-2018-06-18' into staging

Add support for pxelinux.cfg-style network booting to the s390x firmware

# gpg: Signature made Mon 18 Jun 2018 03:59:06 PM CEST
# gpg:                using RSA key 2ED9D774FE702DB5
# gpg: Good signature from "Thomas Huth <th.huth@gmx.de>" [full]
# gpg:                 aka "Thomas Huth <thuth@redhat.com>" [undefined]
# gpg:                 aka "Thomas Huth <huth@tuxfamily.org>" [undefined]
# gpg:                 aka "Thomas Huth <th.huth@posteo.de>" [unknown]

* tag 'tags/s390x-2018-06-18':
  pc-bios/s390-ccw: Update the s390-netboot.img binary
  pc-bios/s390-ccw: Optimize the s390-netboot.img for size
  pc-bios/s390-ccw/net: Try to load pxelinux.cfg file accoring to the UUID
  pc-bios/s390-ccw/net: Add support for pxelinux-style config files
  pc-bios/s390-ccw/net: Update code for the latest changes in SLOF
  roms: Update SLOF submodule to current status
  pc-bios/s390-ccw: define loadparm length

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