staging: comedi: skel: remove driver

The comedi skeleton driver is one of the few "hybrid" drivers with
both legacy and PCI attach mechanisms. Instead of splitting this
driver, just remove it. There are many other comedi drivers that
provide better examples.

Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Reviewed-by: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>