wusb: WHCI host controller driver

A driver for Wireless USB host controllers that comply with the
Wireless Host Controller Interface (HCI) specification as published by
Intel.

The latest publically available version of the specification (0.95) is
supported (except for isochronous transfers).

Build fixes by Randy Dunlap <rdunlap@xenotime.net>

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