btrfs: cleanup btrfs_free_stale_device() usage

We call btrfs_free_stale_device() only when we alloc a new struct
btrfs_device (ret=1), so move it closer to where we alloc the new
device. Also drop the comments.
Signed-off-by: NAnand Jain <anand.jain@oracle.com>
Reviewed-by: NJosef Bacik <jbacik@fb.com>
Reviewed-by: NDavid Sterba <dsterba@suse.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>

fs/btrfs/volumes.c

@@ -782,6 +782,7 @@ static noinline int device_list_add(const char *path,
 
 		ret = 1;
 		device->fs_devices = fs_devices;
+		btrfs_free_stale_device(device);
 	} else if (!device->name || strcmp(device->name->str, path)) {
 		/*
 		 * When FS is already mounted.
@@ -840,13 +841,6 @@ static noinline int device_list_add(const char *path,
 	if (!fs_devices->opened)
 		device->generation = found_transid;
 
-	/*
-	 * if there is new btrfs on an already registered device,
-	 * then remove the stale device entry.
-	 */
-	if (ret > 0)
-		btrfs_free_stale_device(device);
-
 	*fs_devices_ret = fs_devices;
 
 	return ret;