Merge remote-tracking branch 'rth/tags/pull-s390-20170512' into staging

Queued target/s390 patches

# gpg: Signature made Sat 13 May 2017 12:33:08 AM BST
# gpg:                using RSA key 0xAD1270CC4DD0279B
# gpg: Good signature from "Richard Henderson <rth7680@gmail.com>"
# gpg:                 aka "Richard Henderson <rth@redhat.com>"
# gpg:                 aka "Richard Henderson <rth@twiddle.net>"
# Primary key fingerprint: 9CB1 8DDA F8E8 49AD 2AFC  16A4 AD12 70CC 4DD0 279B

* rth/tags/pull-s390-20170512:
  target/s390x: implement serialization in BRANCH CONDITION
  target/s390x: fix SIGNAL PROCESSOR return value
  target/s390x: mask the SIGP order_code using SIGP_ORDER_MASK
  target/s390x: Use atomic operations for LOAD AND OP
  target/s390x: Use atomic operations for COMPARE SWAP
  target/s390x: Implement LOAD PAIR DISJOINT
  target/s390x: Diagnose specification exception for atomics
  target/s390x: Implement LOAD PROGRAM PARAMETER
  target/s390x: Implement STORE FACILITIES LIST EXTENDED

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>