Merge remote-tracking branch 'remotes/borntraeger/tags/s390x-20190930' into staging

Merge remote-tracking branch 'remotes/borntraeger/tags/s390x-20190930' into staging

- do not abuse memory_region_allocate_system_memory and split the memory
  according to KVM memslots in KVM code instead (Paolo, Igor)
- change splitting to split at 4TB (Christian)
- do not claim s390 (31bit) support in configure (Thomas)
- sclp error checking (Janosch, Claudio)
- new s390 pci maintainer (Matt, Collin)
- fix s390 pci (again) (Matt)

# gpg: Signature made Mon 30 Sep 2019 12:52:51 BST
# gpg:                using RSA key 117BBC80B5A61C7C
# gpg: Good signature from "Christian Borntraeger (IBM) <borntraeger@de.ibm.com>" [full]
# Primary key fingerprint: F922 9381 A334 08F9 DBAB  FBCA 117B BC80 B5A6 1C7C

* remotes/borntraeger/tags/s390x-20190930:
  s390/kvm: split kvm mem slots at 4TB
  s390: do not call memory_region_allocate_system_memory() multiple times
  kvm: split too big memory section on several memslots
  kvm: clear dirty bitmaps from all overlapping memslots
  kvm: extract kvm_log_clear_one_slot
  configure: Remove s390 (31-bit mode) from the list of supported CPUs
  s390x: sclp: Report insufficient SCCB length
  s390x: sclp: fix error handling for oversize control blocks
  s390x: sclp: boundary check
  s390x: sclp: refactor invalid command check
  s390: PCI: fix IOMMU region init
  MAINTAINERS: Update S390 PCI Maintainer

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