staging: comedi: me4000: checkpatch.pl cleanup (complex macro)

Fix the checkpatch.pl error:

ERROR: Macros with complex values should be enclosed in parenthesis

This define is not used in the driver. Just remove it.

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>