Merge remote-tracking branch 'remotes/awilliam/tags/vfio-fixes-20180405.0' into staging

VFIO fixes 2018-04-05

 - Convert over zealous error_report to trace point and make more
   meaningful (Eric Auger)

# gpg: Signature made Thu 05 Apr 2018 19:18:06 BST
# gpg:                using RSA key 239B9B6E3BB08B22
# gpg: Good signature from "Alex Williamson <alex.williamson@redhat.com>"
# gpg:                 aka "Alex Williamson <alex@shazbot.org>"
# gpg:                 aka "Alex Williamson <alwillia@redhat.com>"
# gpg:                 aka "Alex Williamson <alex.l.williamson@gmail.com>"
# Primary key fingerprint: 42F6 C04E 540B D1A9 9E7B  8A90 239B 9B6E 3BB0 8B22

* remotes/awilliam/tags/vfio-fixes-20180405.0:
  vfio: Use a trace point when a RAM section cannot be DMA mapped

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