media: tw686x: Register the irq at the end of probe

We got the following warning when booting the kernel:

[    3.243674] INFO: trying to register non-static key.
[    3.243922] The code is fine but needs lockdep annotation, or maybe
[    3.244230] you didn't initialize this object before use?
[    3.245642] Call Trace:
[    3.247836]  lock_acquire+0xff/0x2d0
[    3.248727]  tw686x_audio_irq+0x1a5/0xcc0 [tw686x]
[    3.249211]  tw686x_irq+0x1f9/0x480 [tw686x]

The lock 'vc->qlock' will be initialized in tw686x_video_init(), but the
driver registers the irq before calling the tw686x_video_init(), and we
got the warning.

Fix this by registering the irq at the end of probe

Fixes: 704a84cc ("[media] media: Support Intersil/Techwell TW686x-based video capture cards")
Signed-off-by: Zheyu Ma <zheyuma97@gmail.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>

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

@@ -315,13 +315,6 @@ static int tw686x_probe(struct pci_dev *pci_dev,
 
 	spin_lock_init(&dev->lock);
 
-	err = request_irq(pci_dev->irq, tw686x_irq, IRQF_SHARED,
-			  dev->name, dev);
-	if (err < 0) {
-		dev_err(&pci_dev->dev, "unable to request interrupt\n");
-		goto iounmap;
-	}
-
 	timer_setup(&dev->dma_delay_timer, tw686x_dma_delay, 0);
 
 	/*
@@ -333,18 +326,23 @@ static int tw686x_probe(struct pci_dev *pci_dev,
 	err = tw686x_video_init(dev);
 	if (err) {
 		dev_err(&pci_dev->dev, "can't register video\n");
-		goto free_irq;
+		goto iounmap;
 	}
 
 	err = tw686x_audio_init(dev);
 	if (err)
 		dev_warn(&pci_dev->dev, "can't register audio\n");
 
+	err = request_irq(pci_dev->irq, tw686x_irq, IRQF_SHARED,
+			  dev->name, dev);
+	if (err < 0) {
+		dev_err(&pci_dev->dev, "unable to request interrupt\n");
+		goto iounmap;
+	}
+
 	pci_set_drvdata(pci_dev, dev);
 	return 0;
 
-free_irq:
-	free_irq(pci_dev->irq, dev);
 iounmap:
 	pci_iounmap(pci_dev, dev->mmio);
 free_region: