Merge remote-tracking branch 'sstabellini/tags/xen-20161122-tag' into staging

Xen 2016/11/22

# gpg: Signature made Tue 22 Nov 2016 06:41:23 PM GMT
# gpg:                using RSA key 0x894F8F4870E1AE90
# gpg: Good signature from "Stefano Stabellini <sstabellini@kernel.org>"
# gpg:                 aka "Stefano Stabellini <stefano.stabellini@eu.citrix.com>"
# Primary key fingerprint: D04E 33AB A51F 67BA 07D3  0AEA 894F 8F48 70E1 AE90

* sstabellini/tags/xen-20161122-tag:
  xen: attach pvusb usb bus to backend qdev
  xen: create qdev for each backend device
  qdev: add function qdev_set_id()
  xen: add an own bus for xen backend devices
  xen: fix ioreq handling

Message-id: alpine.DEB.2.10.1611221037010.21858@sstabellini-ThinkPad-X260
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>