Merge remote-tracking branch 'remotes/dg-gitlab/tags/ppc-for-6.0-20210412' into staging

ppc patch queue for 2021-04-21

Here's what I hope is the last ppc related pull request for qemu-6.0.

The 2 patches here revert a behavioural change that after further
discussion we concluded was a bad idea (adding a timeout for
possibly-failed hot unplug requests).  Instead it implements a
different approach to the original problem: we again let unplug
requests the guest doesn't respond to remain pending indefinitely, but
no longer allow those to block attempts to retry the same unplug
again.

The change is a bit more complex than I'd like for this late in the
freeze.  Nonetheless, I think it's important to merge this for 6.0, so
we don't allow a release which has the probably-a-bad-idea timeout
behaviour.

# gpg: Signature made Mon 12 Apr 2021 06:25:58 BST
# gpg:                using RSA key 75F46586AE61A66CC44E87DC6C38CACA20D9B392
# gpg: Good signature from "David Gibson <david@gibson.dropbear.id.au>" [full]
# gpg:                 aka "David Gibson (Red Hat) <dgibson@redhat.com>" [full]
# gpg:                 aka "David Gibson (ozlabs.org) <dgibson@ozlabs.org>" [full]
# gpg:                 aka "David Gibson (kernel.org) <dwg@kernel.org>" [unknown]
# Primary key fingerprint: 75F4 6586 AE61 A66C C44E  87DC 6C38 CACA 20D9 B392

* remotes/dg-gitlab/tags/ppc-for-6.0-20210412:
  spapr.c: always pulse guest IRQ in spapr_core_unplug_request()
  spapr: rollback 'unplug timeout' for CPU hotunplugs

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