Staging: dgnc: fixed some coding style errors

This patch fixes the following checkpatch.pl error:
ERROR: Macros with complex values should be enclosed in parentheses
Outer parentheses were added to macro definitions.

Signed-off-by: Andrew Milkovich <amilkovich@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>