[media] tw686x: Delete an unnecessary check before the function call "video_unregister_device"

The video_unregister_device() function tests whether its argument is NULL
and then returns immediately. Thus the test around the call is not needed.

This issue was detected by using the Coccinelle software.
Signed-off-by: Markus Elfring <elfring@users.sourceforge.net>
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>

drivers/media/pci/tw686x/tw686x-video.c

@@ -1120,8 +1120,7 @@ void tw686x_video_free(struct tw686x_dev *dev)
 	for (ch = 0; ch < max_channels(dev); ch++) {
 		struct tw686x_video_channel *vc = &dev->video_channels[ch];
 
-		if (vc->device)
-			video_unregister_device(vc->device);
+		video_unregister_device(vc->device);
 
 		if (dev->dma_ops->free)
 			for (pb = 0; pb < 2; pb++)