staging: comedi: cd_pcidas64: checkpatch.pl cleanup (void function return)

Fix the checkpatch.pl warning:

WARNING: void function return statements are not generally useful
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/cb_pcidas64.c

@@ -1985,8 +1985,6 @@ static void check_adc_timing(struct comedi_device *dev, struct comedi_cmd *cmd)
 			scan_divisor = min_scan_divisor;
 		cmd->scan_begin_arg = scan_divisor * TIMER_BASE;
 	}
-
-	return;
 }
 
 static int cb_pcidas64_ai_check_chanlist(struct comedi_device *dev,