usb: hook up device authorization to sysfs

Makes it possible to control the authorization of USB devices through
sysfs's /sys/usb/devices/*/authorize.

Update: per Adrian Bunk's suggestion, make dev_attr_authorized_default static

Signed-off-by: Inaky Perez-Gonzalez <inaky@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>