Merge remote-tracking branch 'remotes/cohuck/tags/s390x-20140507' into staging

Merge remote-tracking branch 'remotes/cohuck/tags/s390x-20140507' into staging

Some improvements for s390.

Two patches deal with address translation, one fixes a problem in the
channel subsystem code.

# gpg: Signature made Wed 07 May 2014 09:29:30 BST using RSA key ID C6F02FAF
# gpg: Can't check signature: public key not found

* remotes/cohuck/tags/s390x-20140507:
  s390x/css: Don't save orb in subchannel.
  s390x/helper: Added format control bit to MMU translation
  s390x/helper: Fixed real-to-absolute address translation

Signed-off-by: Peter Maydell <[email protected]>