staging: comedi: dt282x: remove DEBUG define

This define is only used to enable a debug message during the board attach.
The message is just added noise, remove it as well as the DEBUG define.

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>