V4L/DVB (11993): V4L/pwc - use usb_interface as parent, not usb_device

The current code creates a sysfs device path where the video4linux
device is child of the usb device itself instead of the interface it
belongs to. That is evil and confuses udev.

This patch does basically the same thing as Kay's similar patch for the
ov511 driver:

at git commit ce96d0a44a4f8d1bb3dc12b5e98cb688c1bc730d

Signed-off-by: Lennart Poettering <mzxreary@0pointer.de>
Acked-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

drivers/media/video/pwc/pwc-if.c

@@ -1783,7 +1783,7 @@ static int usb_pwc_probe(struct usb_interface *intf, const struct usb_device_id
 		return -ENOMEM;
 	}
 	memcpy(pdev->vdev, &pwc_template, sizeof(pwc_template));
-	pdev->vdev->parent = &(udev->dev);
+	pdev->vdev->parent = &intf->dev;
 	strcpy(pdev->vdev->name, name);
 	video_set_drvdata(pdev->vdev, pdev);