staging: comedi: ni_mio_common: remove unused NI_CS5529_DEBUG code

The code blocked by #ifdef NI_CS5529_DEBUG is not used by the driver.
Just remove it.

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>