attaches to the hub, and HID drivers (ums, ukbd, and uhid) attach to
uhidev. The reason for this change is that some HID devices report multiple
components (like a keyboard and a mouse) using the same interface, but with
different report identifiers. The report identifier can be specified with
a locator for the HID drivers.
Furthermore, change the ukbd driver to handle other formats than the boot
protocol.