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>

drivers/staging/comedi/drivers/me4000.c

@@ -170,7 +170,6 @@ broken.
 
 #define ME4000_AI_MIN_TICKS			66
 #define ME4000_AI_MIN_SAMPLE_TIME		2000
-#define ME4000_AI_BASE_FREQUENCY		(unsigned int) 33E6
 
 #define ME4000_AI_CHANNEL_LIST_COUNT		1024