Merge remote-tracking branch 'remotes/kraxel/tags/usb-20200317-pull-request' into...

usb: bugfixes for usb-serial @ xhci.

# gpg: Signature made Tue 17 Mar 2020 09:50:04 GMT
# gpg:                using RSA key 4CB6D8EED3E87138
# gpg: Good signature from "Gerd Hoffmann (work) <kraxel@redhat.com>" [full]
# gpg:                 aka "Gerd Hoffmann <gerd@kraxel.org>" [full]
# gpg:                 aka "Gerd Hoffmann (private) <kraxel@gmail.com>" [full]
# Primary key fingerprint: A032 8CFF B93A 17A7 9901  FE7D 4CB6 D8EE D3E8 7138

* remotes/kraxel/tags/usb-20200317-pull-request:
  usb-serial: Fix timeout closing the device
  usb-serial: Increase receive buffer to 496
  usb-serial: chunk data to wMaxPacketSize
  usb-serial: Move USB_TOKEN_IN into a helper function

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