firewire: ABI documentation: libhinawa uses firewire-cdev

Hinawa [https://github.com/takaswie/libhinawa/

] is a library for
access to IEEE 1394 devices.  As a gobject introspection library, it
facilitates writing applications in high-level programming languages.
Besides generic I/O via /dev/fw* (firewire-cdev ABI), it also supports
control of IEEE 1394 audio hardware via ALSA hwdep ABIs which are
provided by sound/firewire drivers.

Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>