usb: misc: remove outdated USB LED driver

The USB LED driver exposes a undocumented sysfs interface and doesn't
use the standard kernel LED subsystem. It supports three devices:

Delcom Visual Signal Indicator
The driver supports generation 1 of the device only which was
manufactured until 2008. Remove support for this device completely.

Riso Kagaku RGB LED + Dream Cheeky Webmail Notifier
These devices are HID compliant and are supported by a new USB LED
driver under drivers/hid utilizing the kernel LED subsystem.

So let's remove the old USB LED driver.

Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>