Merge remote-tracking branch 'remotes/cohuck/tags/s390x-20160311' into staging

CPU hotplug via cpu-add for s390x, cleanup of the s390x machine
compat code and a bugfix in the s390-ccw bios.

# gpg: Signature made Fri 11 Mar 2016 09:48:02 GMT using RSA key ID C6F02FAF
# gpg: Good signature from "Cornelia Huck <huckc@linux.vnet.ibm.com>"
# gpg:                 aka "Cornelia Huck <cornelia.huck@de.ibm.com>"

* remotes/cohuck/tags/s390x-20160311:
  s390x/cpu: use g_new0
  s390x: Introduce S390MachineClass
  s390x: Introduce machine definition macros
  pc-bios/s390-ccw: fix old bug in ptr increment
  s390x/cpu: Allow hotplug of CPUs
  s390x/cpu: Add error handling to cpu creation
  s390x/cpu: Add CPU property links
  s390x/cpu: Tolerate max_cpus
  s390x/cpu: Get rid of side effects when creating a vcpu
  s390x/cpu: Set initial CPU state in common routine
  s390x/cpu: Cleanup init in preparation for hotplug

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