Merge remote-tracking branch 'remotes/cohuck/tags/s390x-20201211' into staging

Merge remote-tracking branch 'remotes/cohuck/tags/s390x-20201211' into staging

First set of 6.0 patches for s390x:
- acceptance test for device detection
- bugfixes

# gpg: Signature made Fri 11 Dec 2020 12:21:45 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/tags/s390x-20201211:
  s390x/cpu: Use timer_free() in the finalize function to avoid memleaks
  tests/acceptance: test s390x zpci fid propagation
  tests/acceptance: verify s390x device detection
  tests/acceptance: test virtio-ccw revision handling
  tests/acceptance: add a test for devices on s390x
  hw/watchdog/wdt_diag288: Remove unnecessary includes

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