usb: misc: adutux: use swap()

Use swap() in order to make code cleaner. Issue found by coccinelle.

Signed-off-by: Salah Triki <salah.triki@gmail.com>
Link: https://lore.kernel.org/r/20210803005343.GA1578854@pc
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/misc/adutux.c

@@ -394,13 +394,10 @@ static ssize_t adu_read(struct file *file, __user char *buffer, size_t count,
 			spin_lock_irqsave (&dev->buflock, flags);
 			if (dev->read_buffer_length) {
 				/* we secure access to the primary */
-				char *tmp;
 				dev_dbg(&dev->udev->dev,
 					"%s : swap, read_buffer_length = %d\n",
 					__func__, dev->read_buffer_length);
-				tmp = dev->read_buffer_secondary;
-				dev->read_buffer_secondary = dev->read_buffer_primary;
-				dev->read_buffer_primary = tmp;
+				swap(dev->read_buffer_primary, dev->read_buffer_secondary);
 				dev->secondary_head = 0;
 				dev->secondary_tail = dev->read_buffer_length;
 				dev->read_buffer_length = 0;