Merge remote-tracking branch 'remotes/gkurz/tags/9p-next-2020-05-14' into staging

Changes:
- Christian Schoenebeck is now co-maintainer for 9pfs
- relax checks for O_NOATIME
- minor documentation updates

# gpg: Signature made Thu 14 May 2020 08:14:37 BST
# gpg:                using RSA key B4828BAF943140CEF2A3491071D4D5E5822F73D6
# gpg: Good signature from "Greg Kurz <groug@kaod.org>" [full]
# gpg:                 aka "Gregory Kurz <gregory.kurz@free.fr>" [full]
# gpg:                 aka "[jpeg image of size 3330]" [full]
# Primary key fingerprint: B482 8BAF 9431 40CE F2A3  4910 71D4 D5E5 822F 73D6

* remotes/gkurz/tags/9p-next-2020-05-14:
  xen-9pfs: Fix log messages of reply errors
  9pfs: local: ignore O_NOATIME if we don't have permissions
  qemu-options.hx: 9p: clarify -virtfs vs. -fsdev
  MAINTAINERS: Upgrade myself as 9pfs co-maintainer

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