Two PCI fixes/improvements for s390x.

# gpg: Signature made Mon 31 Oct 2016 10:09:24 GMT
# gpg:                using RSA key 0xDECF6B93C6F02FAF
# gpg: Good signature from "Cornelia Huck <huckc@linux.vnet.ibm.com>"
# gpg:                 aka "Cornelia Huck <cornelia.huck@de.ibm.com>"
# Primary key fingerprint: C3D0 D66D C362 4FF6 A8C0  18CE DECF 6B93 C6F0 2FAF

* remotes/cohuck/tags/s390x-20161031:
  s390x/pci: Check memory region dispatching callbacks
  s390x/pci: use generic interface to inject interrupt
Signed-off-by: NPeter Maydell <peter.maydell@linaro.org>