This is a fairly big rewrite regarding the card resource management in
line6 drivers:
- The card creation is moved into line6_probe(). This adds the global
destructor to private_free, so that each driver doesn't have to call
it any longer.
- The USB disconnect callback handles the card release, thus each
driver needs to concentrate on only its own resources. No need to
snd_card_*() call in the destructor.
- Fix the potential stall in disconnection by removing
snd_card_free(). It's replaced with snd_card_free_when_closed()
for asynchronous release.
- The only remaining operation for the card in each driver is the call
of snd_card_register(). All the rest are dealt in the common module
by itself.
- These ended up with removal of audio.[ch] as a result of a reduction
of one layer. Each driver just needs to call line6_probe().
Tested-by: Chris Rorvick <chris@rorvick.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>