wusb: add the Wireless USB core

Add support for Ceritified Wireless USB 1.0 to the USB stack.

This has been split into several patches for easier review.

core (this patch):
  - host controller infrastructure
  - cluster reservation
  - UWB PAL registration
  - fake root hub

protocol:
  - MMC management (start/stop, managing IEs)
  - device connection

security:
  - device authentication and authorization

build-system:
  - Kconfig and Kbuild files

Signed-off-by: David Vrabel <david.vrabel@csr.com>