ALSA: hda/hdmi: Static PCM mapping again with AMD HDMI codecs

The recent code refactoring for HD-audio HDMI codec driver caused a
regression on AMD/ATI HDMI codecs; namely, PulseAudioand pipewire
don't recognize HDMI outputs any longer while the direct output via
ALSA raw access still works.

The problem turned out that, after the code refactoring, the driver
assumes only the dynamic PCM assignment, and when a PCM stream that
still isn't assigned to any pin gets opened, the driver tries to
assign any free converter to the PCM stream.  This behavior is OK for
Intel and other codecs, as they have arbitrary connections between
pins and converters.  OTOH, on AMD chips that have a 1:1 mapping
between pins and converters, this may end up with blocking the open of
the next PCM stream for the pin that is tied with the formerly taken
converter.

Also, with the code refactoring, more PCM streams are exposed than
necessary as we assume all converters can be used, while this isn't
true for AMD case.  This may change the PCM stream assignment and
confuse users as well.

This patch fixes those problems by:

- Introducing a flag spec->static_pcm_mapping, and if it's set, the
  driver applies the static mapping between pins and converters at the
  probe time
- Limiting the number of PCM streams per pins, too; this avoids the
  superfluous PCM streams

Fixes: ef6f5494

 ("ALSA: hda/hdmi: Use only dynamic PCM device allocation")
Cc: <stable@vger.kernel.org>
Link: https://bugzilla.kernel.org/show_bug.cgi?id=216836
Co-developed-by: Jaroslav Kysela <perex@perex.cz>
Signed-off-by: Jaroslav Kysela <perex@perex.cz>
Link: https://lore.kernel.org/r/20221228125714.16329-1-tiwai@suse.de
Signed-off-by: Takashi Iwai <tiwai@suse.de>