Merge remote-tracking branch 'remotes/kraxel/tags/fixes-20210326-pull-request' into staging

fixes for usb, virtio-gpu and vhost-gpu

# gpg: Signature made Fri 26 Mar 2021 12:49:14 GMT
# gpg:                using RSA key A0328CFFB93A17A79901FE7D4CB6D8EED3E87138
# 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/fixes-20210326-pull-request:
  hw/usb/hcd-ehci: Fix crash when showing help of EHCI devices
  s390x: modularize virtio-gpu-ccw
  s390x: add have_virtio_ccw
  s390x: move S390_ADAPTER_SUPPRESSIBLE
  hw/usb/hcd-ehci-sysbus: Free USBPacket on instance finalize()
  vhost-user-gpu: fix cursor move/update
  vhost-user-gpu: fix vugbm_device_init fallback
  vhost-user-gpu: glFlush before notifying clients
  usb: Remove "-usbdevice ccid"

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