Merge remote-tracking branch 'remotes/stefanberger/tags/pull-tpm-2020-07-24-1' into...

Merge remote-tracking branch 'remotes/stefanberger/tags/pull-tpm-2020-07-24-1' into staging

Merge tpm 2020/07/24 v1

# gpg: Signature made Sat 25 Jul 2020 01:13:22 BST
# gpg:                using RSA key B818B9CADF9089C2D5CEC66B75AD65802A0B4211
# gpg: Good signature from "Stefan Berger <stefanb@linux.vnet.ibm.com>" [unknown]
# 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-2020-07-24-1:
  tpm_emulator: Report an error if chardev is missing
  tpm: Improve help on TPM types when none are available
  Revert "tpm: Clean up error reporting in tpm_init_tpmdev()"

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