Merge remote-tracking branch 'remotes/ehabkost/tags/x86-pull-request' into staging

Merge remote-tracking branch 'remotes/ehabkost/tags/x86-pull-request' into staging

X86 queue, 2015-11-05

# gpg: Signature made Thu 05 Nov 2015 19:35:31 GMT using RSA key ID 984DC5A6
# gpg: Good signature from "Eduardo Habkost <ehabkost@redhat.com>"

* remotes/ehabkost/tags/x86-pull-request:
  target-i386: Enable clflushopt/clwb/pcommit instructions
  target-i386: Remove POPCNT from qemu64 and qemu32 CPU models
  target-i386: Remove ABM from qemu64 CPU model
  target-i386: Remove SSE4a from qemu64 CPU model
  target-i386: Set "check=off" by default on pc-*-2.4 and older

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