Merge remote-tracking branch 'remotes/afaerber/tags/qom-cpu-for-peter' into staging

QOM CPUState and X86CPU

* Include exception state in CPU VMState
* Fix -cpu *,migratable=foo
* Error out on unknown -cpu *,+foo,-bar

# gpg: Signature made Fri 05 Sep 2014 15:38:14 BST using RSA key ID 3E7E013F
# gpg: Good signature from "Andreas Färber <[email protected]>"
# gpg:                 aka "Andreas Färber <[email protected]>"

* remotes/afaerber/tags/qom-cpu-for-peter:
  target-i386: Reject invalid CPU feature names on the command-line
  target-i386: Support migratable=no properly
  exec: Save CPUState::exception_index field

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