Merge remote-tracking branch 'remotes/kraxel/tags/pull-usb-20170221-1' into staging

xhci: add qemu-xhci device, some followup cleanups.
ccid: better sanity checking.
ehci: fix memory leak
ohci: bugfixes.

# gpg: Signature made Tue 21 Feb 2017 07:14:35 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-usb-20170221-1:
  usb-ccid: add check message size checks
  usb-ccid: move header size check
  usb-ccid: better bulk_out error handling
  xhci: drop via vendor command handling
  xhci: fix nec vendor quirk handling
  xhci: add qemu xhci controller
  xhci: drop ER_FULL_HACK workaround
  xhci: apply limits to loops
  usb: ohci: limit the number of link eds
  usb: ohci: fix error return code in servicing iso td
  usb: ehci: fix memory leak in ehci

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