staging: comedi: cb_das16_cs: remove unused timer subdevice

The timer subdevice is never initialized due to the 'if (0)'. The
comedi callbacks also don't do anything and just return -EINVAL.

Remove the subdevice and associated code.

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