[media] media: Fix media device minor registration

The find_next_zero_bit() is called with the from and to arguments in the
wrong order. This results in the function always returning 0, and all
media devices being registered with minor 0. Furthermore, mdev->minor is
then used before being assigned with the find_next_zero_bit() return
value. This really makes sure we'll always use minor 0.

Fix this and let the system support more than one media device.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Cc: stable@kernel.org
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

drivers/media/media-devnode.c

@@ -213,14 +213,14 @@ int __must_check media_devnode_register(struct media_devnode *mdev)
 
 	/* Part 1: Find a free minor number */
 	mutex_lock(&media_devnode_lock);
-	minor = find_next_zero_bit(media_devnode_nums, 0, MEDIA_NUM_DEVICES);
+	minor = find_next_zero_bit(media_devnode_nums, MEDIA_NUM_DEVICES, 0);
 	if (minor == MEDIA_NUM_DEVICES) {
 		mutex_unlock(&media_devnode_lock);
 		printk(KERN_ERR "could not get a free minor\n");
 		return -ENFILE;
 	}
 
-	set_bit(mdev->minor, media_devnode_nums);
+	set_bit(minor, media_devnode_nums);
 	mutex_unlock(&media_devnode_lock);
 
 	mdev->minor = minor;