Merge remote-tracking branch 'remotes/vivier2/tags/trivial-branch-for-6.2-pull-reques...

Trivial patches pull request 20210927

# gpg: Signature made Mon 27 Sep 2021 10:52:10 BST
# gpg:                using RSA key CD2F75DDC8E3A4DC2E4F5173F30C38BD3F2FBE3C
# gpg:                issuer "laurent@vivier.eu"
# gpg: Good signature from "Laurent Vivier <lvivier@redhat.com>" [full]
# gpg:                 aka "Laurent Vivier <laurent@vivier.eu>" [full]
# gpg:                 aka "Laurent Vivier (Red Hat) <lvivier@redhat.com>" [full]
# Primary key fingerprint: CD2F 75DD C8E3 A4DC 2E4F  5173 F30C 38BD 3F2F BE3C

* remotes/vivier2/tags/trivial-branch-for-6.2-pull-request:
  multi-process: fix usage information
  hmp: Drop a bogus sentence from set_password's documentation
  hmp: Unbreak "change vnc"
  hw/loader: Restrict PC_ROM_* definitions to hw/i386/pc
  docs/nvdimm: Update nvdimm option value in machine example

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