[media] dvb-usb-v2: add pointer to 'struct usb_interface' for driver usage

Top level pointer on USB probe is struct usb_interface *. Add that
pointer to struct dvb_usb_device that drivers could use it, for
dev_* logging and more.
Signed-off-by: Antti Palosaari <crope@iki.fi>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>

drivers/media/usb/dvb-usb-v2/dvb_usb.h

@@ -354,6 +354,7 @@ struct dvb_usb_adapter {
  * @name: device name
  * @rc_map: name of rc codes table
  * @rc_polling_active: set when RC polling is active
+ * @intf: pointer to the device's struct usb_interface
  * @udev: pointer to the device's struct usb_device
  * @rc: remote controller configuration
  * @powered: indicated whether the device is power or not
@@ -370,6 +371,7 @@ struct dvb_usb_device {
 	const char *name;
 	const char *rc_map;
 	bool rc_polling_active;
+	struct usb_interface *intf;
 	struct usb_device *udev;
 	struct dvb_usb_rc rc;
 	int powered;

drivers/media/usb/dvb-usb-v2/dvb_usb_core.c

@@ -868,6 +868,7 @@ int dvb_usbv2_probe(struct usb_interface *intf,
 		goto err;
 	}
 
+	d->intf = intf;
 	d->name = driver_info->name;
 	d->rc_map = driver_info->rc_map;
 	d->udev = udev;