V4L/DVB (13549): v4l: Add video_device_node_name function

Many drivers access the device number (video_device::v4l2_devnode::num)
in order to print the video device node name. Add and use a helper
function to retrieve the video_device node name.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
diff --git a/drivers/media/video/v4l2-dev.c b/drivers/media/video/v4l2-dev.c
index 500cbe9..aa3e0f9 100644
--- a/drivers/media/video/v4l2-dev.c
+++ b/drivers/media/video/v4l2-dev.c
@@ -551,8 +551,8 @@
 	vdev->dev.release = v4l2_device_release;
 
 	if (nr != -1 && nr != vdev->num && warn_if_nr_in_use)
-		printk(KERN_WARNING "%s: requested %s%d, got %s%d\n",
-				__func__, name_base, nr, name_base, vdev->num);
+		printk(KERN_WARNING "%s: requested %s%d, got %s\n", __func__,
+			name_base, nr, video_device_node_name(vdev));
 
 	/* Part 5: Activate this minor. The char device can now be used. */
 	mutex_lock(&videodev_lock);