staging: comedi: c6xdigio: change first param to c6xdigio_chk_status()

For aesthetics, pass the comedi_device pointer instead of the dev->iobase
as the first parameter.

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>