staging: dgap: Macros with complex values should be enclosed in parenthesis

This patch fixes a checkpatch warning
"Macros with complex values should be enclosed in parenthesis"
Signed-off-by: Mark Hounschell <markh@compro.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/dgap/dgap.h

@@ -186,7 +186,7 @@ typedef unsigned char		uchar;
 			ECHOCTL | ECHOKE | IEXTEN)
 
 #ifndef _POSIX_VDISABLE
-#define   _POSIX_VDISABLE '\0'
+#define _POSIX_VDISABLE ('\0')
 #endif
 
 #define SNIFF_MAX	65536		/* Sniff buffer size (2^n) */