ALSA: oxfw: code refactoring for existent device entry with specifier_id and version

ALSA: oxfw: code refactoring for existent device entry with specifier_id and version

All of the devices known to be based on OXFW ASICs have the same layout
of configuration ROM, in which unit directory includes vendor, model,
specifier_id and version immediate values. Especially, the pair of
specifier_id and version is fixed to represent AV/C general protocol.

This commit refactors device entries to fulfil with these 4 elements.

Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Link: https://lore.kernel.org/r/20210518084557.102681-4-o-takashi@sakamocchi.jp
Signed-off-by: Takashi Iwai <tiwai@suse.de>