staging: comedi: remove an unneeded variable

"chanlist" was left over, we don't need it any more.
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Reviewed-by: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/comedi/comedi_fops.c

@@ -1597,7 +1597,6 @@ static int do_cmdtest_ioctl(struct comedi_device *dev,
 {
 	struct comedi_cmd cmd;
 	struct comedi_subdevice *s;
-	unsigned int *chanlist = NULL;
 	unsigned int __user *user_chanlist;
 	int ret;
 
@@ -1626,8 +1625,6 @@ static int do_cmdtest_ioctl(struct comedi_device *dev,
 		ret = -EFAULT;
 	}
 
-	kfree(chanlist);
-
 	return ret;
 }