[media] media-devnode: just return 0 instead of using a var

Instead of allocating a var to store 0 and just return it,
change the code to return 0 directly.

Signed-off-by: Mauro Carvalho Chehab <[e-mail]>

drivers/media/media-devnode.c

···
 static int media_release(struct inode *inode, struct file *filp)
 {
 	struct media_devnode *mdev = media_devnode_data(filp);
-	int ret = 0;
 
 	if (mdev->fops->release)
 		mdev->fops->release(filp);
···
 	   return value is ignored. */
 	put_device(&mdev->dev);
 	filp->private_data = NULL;
-	return ret;
+	return 0;
 }
 
 static const struct file_operations media_devnode_fops = {