Merge remote-tracking branch 'remotes/dgibson/tags/ppc-for-4.1-20190813' into staging

ppc patch queue 2019-08-13 (last minute qemu-4.1 fixes)

Here's a very, very last minute pull request for qemu-4.1.  This fixes
two nasty bugs with the XIVE interrupt controller in "dual" mode
(where the guest decides which interrupt controller it wants to use).
One occurs when resetting the guest while I/O is active, and the other
with migration of hotplugged CPUs.

The timing here is very unfortunate.  Alas, we only spotted these bugs
very late, and I was sick last week, delaying analysis and fix even
further.

This series hasn't had nearly as much testing as I'd really like, but
I'd still like to squeeze it into qemu-4.1 if possible, since
definitely fixing two bad bugs seems like an acceptable tradeoff for
the risk of introducing different bugs.

# gpg: Signature made Tue 13 Aug 2019 07:56:42 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/dgibson/tags/ppc-for-4.1-20190813:
  spapr/xive: Fix migration of hot-plugged CPUs
  spapr: Reset CAS & IRQ subsystem after devices

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