Merge remote-tracking branch 'remotes/cohuck/tags/s390x-20170919-v2' into staging

Assorted s390x patches:
- introduce virtio-gpu-ccw, with virtio-gpu endian fixes
- lots of cleanup in the s390x code
- make device_add work for s390x cpus
- enable seccomp on s390x
- an ivshmem endian fix
- set the reserved DHCP client architecture id for netboot
- fixes in the css and pci support

# gpg: Signature made Tue 19 Sep 2017 17:39:45 BST
# gpg:                using RSA key 0xDECF6B93C6F02FAF
# gpg: Good signature from "Cornelia Huck <conny@cornelia-huck.de>"
# gpg:                 aka "Cornelia Huck <huckc@linux.vnet.ibm.com>"
# gpg:                 aka "Cornelia Huck <cornelia.huck@de.ibm.com>"
# gpg:                 aka "Cornelia Huck <cohuck@kernel.org>"
# gpg:                 aka "Cornelia Huck <cohuck@redhat.com>"
# Primary key fingerprint: C3D0 D66D C362 4FF6 A8C0  18CE DECF 6B93 C6F0 2FAF

* remotes/cohuck/tags/s390x-20170919-v2: (38 commits)
  MAINTAINERS/s390x: add terminal3270.c
  virtio-ccw: Create a virtio gpu device for the ccw bus
  virtio-gpu: Handle endian conversion
  s390x/ccw: create s390 phb for compat reasons as well
  configure: Allow --enable-seccomp on s390x, too
  virtio-ccw: remove stale comments on endianness
  s390x: allow CPU hotplug in random core-id order
  s390x: generate sclp cpu information from possible_cpus
  s390x: get rid of cpu_s390x_create()
  s390x: get rid of cpu_states and use possible_cpus instead
  s390x: implement query-hotpluggable-cpus
  s390x: CPU hot unplug via device_del cannot work for now
  s390x: allow cpu hotplug via device_add
  s390x: print CPU definitions in sorted order
  target/s390x: rename next_cpu_id to next_core_id
  target/s390x: use "core-id" for cpu number/address/id handling
  target/s390x: set cpu->id for linux user when realizing
  s390x: allow only 1 CPU with TCG
  target/s390x: use program_interrupt() in per_check_exception()
  target/s390x: use trigger_pgm_exception() in s390_cpu_handle_mmu_fault()
  ...

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>