Merge remote-tracking branch 'remotes/cohuck-gitlab/tags/s390x-20210121' into staging

Merge remote-tracking branch 'remotes/cohuck-gitlab/tags/s390x-20210121' into staging

s390x updates:
- headers update to Linux 5.11-rc2
- fix tcg emulation for some instructions that are generated by
  clang Linux kernel builds
- vfio-ccw: wire up the device unplug notification mechanism
- fix a gcc 11 warning

# gpg: Signature made Thu 21 Jan 2021 12:08:12 GMT
# gpg:                using RSA key C3D0D66DC3624FF6A8C018CEDECF6B93C6F02FAF
# gpg:                issuer "cohuck@redhat.com"
# gpg: Good signature from "Cornelia Huck <conny@cornelia-huck.de>" [unknown]
# gpg:                 aka "Cornelia Huck <huckc@linux.vnet.ibm.com>" [full]
# gpg:                 aka "Cornelia Huck <cornelia.huck@de.ibm.com>" [full]
# gpg:                 aka "Cornelia Huck <cohuck@kernel.org>" [unknown]
# gpg:                 aka "Cornelia Huck <cohuck@redhat.com>" [unknown]
# Primary key fingerprint: C3D0 D66D C362 4FF6 A8C0  18CE DECF 6B93 C6F0 2FAF

* remotes/cohuck-gitlab/tags/s390x-20210121:
  s390x: Use strpadcpy for copying vm name
  vfio-ccw: Connect the device request notifier
  Update linux headers to 5.11-rc2
  update-linux-headers: Include const.h
  s390x/tcg: Ignore register content if b1/b2 is zero when handling EXECUTE
  tests/tcg/s390x: Fix EXRL tests
  s390x/tcg: Don't ignore content in r0 when not specified via "b" or "x"
  s390x/tcg: Fix RISBHG
  s390x/tcg: Fix ALGSI

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