Merge remote-tracking branch 'remotes/agraf/tags/signed-s390-for-upstream' into staging

Patch queue for s390 - 2017-04-25

Two simple fixes this time around:

  - fix BQL for s390 virtio target
  - Fix SIGP emulation

# gpg: Signature made Tue 25 Apr 2017 12:40:38 BST
# gpg:                using RSA key 0x2B33791E03FEDC60
# gpg: Good signature from "Alexander Graf <agraf@suse.de>"
# gpg:                 aka "Alexander Graf <alex@csgraf.de>"
# Primary key fingerprint: 7F2A 4C87 F94C 5EFE DBC3  75DC 1631 30DA 5B24 530A
#      Subkey fingerprint: 54D3 364F A6C3 60FF AF81  EB53 2B33 791E 03FE DC60

* remotes/agraf/tags/signed-s390-for-upstream:
  s390x/misc_helper.c: wrap s390_virtio_hypercall in BQL
  target-s390x: Mask the SIGP order_code to 8bit.

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