btrfs: remove the bio argument from finish_compressed_bio_read

This bio is usually one of the compressed bio's, and we don't actually
need it in this function, so remove the argument and stop passing it
around.

Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>