Currently the 'refs_to_drop' argument of __btrfs_free_extent() always
matches the value of node->ref_mod, so remove the argument and use
node->ref_mod at __btrfs_free_extent().
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>