Merge remote-tracking branch 'remotes/cohuck/tags/s390x-20150330' into staging

s390x fixes:
- virtqueue index issues in virtio-ccw
- cleanup and sign extension fix for the ipl device

# gpg: Signature made Mon Mar 30 08:52:54 2015 BST 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-20150330:
  s390x/ipl: avoid sign extension
  s390x: do not include ram_addr.h
  virtio-ccw: range check in READ_VQ_CONF
  virtio-ccw: fix range check for SET_VQ

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