Apple machines with multiple speakers typically have the shutdown pin of

Apple machines with multiple speakers typically have the shutdown pin of
the digital amplifier codecs wired up to a single GPIO.  This is apparently
problematic for Linux and Asahi Linux changed their device trees to use a
regulator instead to such that reference counting makes sure that shutdown
isn't asserted until all codecs are ready for it.  Follow suit, even though
our regulator code doesn't do the proper reference counting yet.

ok patrick@