Merge remote-tracking branch 'remotes/kraxel/tags/pull-vga-20170202-2' into staging

Merge remote-tracking branch 'remotes/kraxel/tags/pull-vga-20170202-2' into staging

cirrus: multiple bugfixes, including CVE-2017-2615 fix.

# gpg: Signature made Thu 02 Feb 2017 15:03:35 GMT
# gpg:                using RSA key 0x4CB6D8EED3E87138
# gpg: Good signature from "Gerd Hoffmann (work) <kraxel@redhat.com>"
# gpg:                 aka "Gerd Hoffmann <gerd@kraxel.org>"
# gpg:                 aka "Gerd Hoffmann (private) <kraxel@gmail.com>"
# Primary key fingerprint: A032 8CFF B93A 17A7 9901  FE7D 4CB6 D8EE D3E8 7138

* remotes/kraxel/tags/pull-vga-20170202-2:
  cirrus: fix oob access issue (CVE-2017-2615)
  cirrus: fix blit address mask handling
  cirrus: allow zero source pitch in pattern fill rops
  cirrus: handle negative pitch in cirrus_invalidate_region()

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