[media] ddbridge: Do not free_irq() if request_irq() failed

My static checker detected that free_irq() is called even after
request_irq() failed in ddb_probe(). In this case, the kernel may try to
free dev->pdev->irq although the IRQ is not assigned. This event rarely
occurs, but always introduces a warning if it happens.

"goto fail1" always results in disabling enabled MSI and releasing a
requested IRQ. It seems like the former handling is necessary. So I added
a conditional branch before the free_irq() (stat == 0 means request_irq()
succeeds).

Signed-off-by: Takeshi Yoshimura <yos@sslab.ics.keio.ac.jp>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>

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

@@ -1630,7 +1630,8 @@ fail1:
 	printk(KERN_ERR "fail1\n");
 	if (dev->msi)
 		pci_disable_msi(dev->pdev);
-	free_irq(dev->pdev->irq, dev);
+	if (stat == 0)
+		free_irq(dev->pdev->irq, dev);
 fail:
 	printk(KERN_ERR "fail\n");
 	ddb_unmap(dev);