Merge remote-tracking branch 'remotes/thuth/tags/pull-request-2021-10-15' into staging

* Check kernel command line size on s390x
* Simplification of one of the SIGP instructions on s390x
* Cornelia stepping down as maintainer in some subsystems
* Update the dtc submodule to a proper release version

# gpg: Signature made Fri 15 Oct 2021 02:11:13 AM PDT
# gpg:                using RSA key 27B88847EEE0250118F3EAB92ED9D774FE702DB5
# gpg:                issuer "thuth@redhat.com"
# gpg: Good signature from "Thomas Huth <th.huth@gmx.de>" [full]
# gpg:                 aka "Thomas Huth <thuth@redhat.com>" [full]
# gpg:                 aka "Thomas Huth <th.huth@posteo.de>" [unknown]
# gpg:                 aka "Thomas Huth <huth@tuxfamily.org>" [full]

* remotes/thuth/tags/pull-request-2021-10-15:
  dtc: Update to version 1.6.1
  s390x virtio-ccw machine: step down as maintainer
  s390x/kvm: step down as maintainer
  vfio-ccw: step down as maintainer
  s390x: sigp: Force Set Architecture to return Invalid Parameter
  s390x/ipl: check kernel command line size

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

diff --cc MAINTAINERS
Simple merge