This makes the code flow easier -- instead of the controller driver
calling snd_hda_build_pcms() and snd_hda_build_controls() explicitly,
the codec driver itself builds PCMs and controls at probe time.  Then
the controller driver only needs to call snd_card_register().

Also, this allows us the full bind/unbind control, too.  Even when a
codec driver is bound later, it automatically registers the new PCM
and controls by itself.
Signed-off-by: NTakashi Iwai <tiwai@suse.de>