staging: comedi: das08_cs: move the comedi_driver variable

Move the comedi_driver variable to remove the need for the
forward declarations. Add some whitespace to the declaration
for aesthetic reasons.

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