Staging: comedi: Compressed two lines of code into one.

The following patch compressed two lines of code into one using
coccinelle and removed an unused variable.
The semantic patch used is as follows:

@@
expression ret;
identifier f;
@@

-ret =
+return
     f(...);
-return ret;
Signed-off-by: Heena Sirwani <heenasirwani@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/comedi/comedi_fops.c

@@ -1718,7 +1718,6 @@ static int do_cancel_ioctl(struct comedi_device *dev, unsigned int arg,
 			   void *file)
 {
 	struct comedi_subdevice *s;
-	int ret;
 
 	if (arg >= dev->n_subdevices)
 		return -EINVAL;
@@ -1732,9 +1731,7 @@ static int do_cancel_ioctl(struct comedi_device *dev, unsigned int arg,
 	if (s->busy != file)
 		return -EBUSY;
 
-	ret = do_cancel(dev, s);
-
-	return ret;
+	return do_cancel(dev, s);
 }
 
 /*