Merge remote-tracking branch 'remotes/awilliam/tags/vfio-fixes-20200106.0' into staging

VFIO fixes 2020-01-06

 - Fix irqchip notifier de-registration if not registered (Peter Xu)

# gpg: Signature made Mon 06 Jan 2020 21:58:17 GMT
# gpg:                using RSA key 239B9B6E3BB08B22
# gpg: Good signature from "Alex Williamson <alex.williamson@redhat.com>" [full]
# gpg:                 aka "Alex Williamson <alex@shazbot.org>" [full]
# gpg:                 aka "Alex Williamson <alwillia@redhat.com>" [full]
# gpg:                 aka "Alex Williamson <alex.l.williamson@gmail.com>" [full]
# Primary key fingerprint: 42F6 C04E 540B D1A9 9E7B  8A90 239B 9B6E 3BB0 8B22

* remotes/awilliam/tags/vfio-fixes-20200106.0:
  vfio/pci: Don't remove irqchip notifier if not registered

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