USB: usbfs: deprecate and hide option for !embedded

Modern systems do not use usbfs; the entries within it are files,
not device nodes, and do not support ACLs which are the default way to
provide access to USB devices to untrusted users.

It is replaced by device-nodes maintained by udev in /dev/bus/usb,
libusb uses this device nodes.

Mark the option as deprecated, and hide entirely for non-embedded builds
(which may not be using udev but require raw USB device access).

Signed-off-by: Scott James Remnant <scott@canonical.com>
Acked-by: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>