staging: comedi: mpc8260cpm: remove driver

This driver is incomplete and seriously broken. It can't be enabled
in the Kconfig and it's not even set up to be compiled.

Just remove it.

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