Merge remote-tracking branch 'remotes/otubo/tags/pull-seccomp-20160416' into staging

seccomp branch queue

# gpg: Signature made Sat 16 Apr 2016 19:58:46 BST using RSA key ID 12F8BD2F
# gpg: Good signature from "Eduardo Otubo (Software Engineer @ ProfitBricks) <eduardo.otubo@profitbricks.com>"
# gpg: WARNING: This key is not certified with a trusted signature!
# gpg:          There is no indication that the signature belongs to the owner.
# Primary key fingerprint: 1C96 46B6 E1D1 C38A F2EC  3FDE FD0C FF5B 12F8 BD2F

* remotes/otubo/tags/pull-seccomp-20160416:
  seccomp: adding sysinfo system call to whitelist
  seccomp: Whitelist cacheflush since 2.2.0 not 2.2.3
  configure: Enable seccomp sandbox for MIPS

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