Merge remote-tracking branch 'kraxel/usb.84' into staging

# By Andreas Färber (3) and others
# Via Gerd Hoffmann
* kraxel/usb.84:
  usb: fix serial number for hid devices
  usb: add serial bus property
  usb-host-libusb: set USB_DEV_FLAG_IS_HOST
  usb/host-libusb: Fix building with libusb git master code
  usb/hcd-ehci: Add Faraday FUSBH200 support
  usb/hcd-ehci: Replace PORTSC macros with variables
  usb/hcd-ehci: Add Tegra2 SysBus EHCI device
  usb/hcd-ehci: Split off instance_init from realize
  usb/hcd-ehci-sysbus: Convert to QOM realize