ALSA: core: Introduce snd_device_alloc()

Introduce a new helper, snd_device_alloc(), for allocating a struct
device that is bound with the sound class.  It's a replacement of
snd_device_initialize().

Reviewed-by: Jaroslav Kysela <perex@perex.cz>
Signed-off-by: Curtis Malainey <cujomalainey@chromium.org>
Tested-by: Curtis Malainey <cujomalainey@chromium.org>
Link: https://lore.kernel.org/r/20230816160252.23396-2-tiwai@suse.de
Signed-off-by: Takashi Iwai <tiwai@suse.de>