Merge remote-tracking branch 'remotes/borntraeger/tags/s390x-20180323' into staging

s390x: Fixes for 2.12

- Fix for the s390 cpumodel
- Forbid multifunction PCI devices

# gpg: Signature made Fri 23 Mar 2018 09:06:31 GMT
# gpg:                using RSA key 117BBC80B5A61C7C
# gpg: Good signature from "Christian Borntraeger (IBM) <borntraeger@de.ibm.com>"
# Primary key fingerprint: F922 9381 A334 08F9 DBAB  FBCA 117B BC80 B5A6 1C7C

* remotes/borntraeger/tags/s390x-20180323:
  s390x/cpumodel: fix feature groups and breakage of MSA8
  s390x/pci: forbid multifunction pci device

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