Merge remote-tracking branch 'remotes/stefanberger/tags/pull-tpm-2018-05-23-4' into...

Merge remote-tracking branch 'remotes/stefanberger/tags/pull-tpm-2018-05-23-4' into staging

Merge tpm 2018/05/23 v4

# gpg: Signature made Sat 26 May 2018 03:52:12 BST
# gpg:                using RSA key 75AD65802A0B4211
# gpg: Good signature from "Stefan Berger <stefanb@linux.vnet.ibm.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: B818 B9CA DF90 89C2 D5CE  C66B 75AD 6580 2A0B 4211

* remotes/stefanberger/tags/pull-tpm-2018-05-23-4:
  test: Add test cases that use the external swtpm with CRB interface
  docs: tpm: add VM save/restore example and troubleshooting guide
  tpm: extend TPM TIS with state migration support
  tpm: extend TPM emulator with state migration support

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