ALSA: hda - Use common codes for ATI, Nvidia and VIA simple codecs

The code refactoring using the same helper functions for sharing the
codes among ATI, Nvidia and VIA simple_hdmi* stuff.  Except for that
spec->pcm_playback is no longer pointer, the functionality doesn't
change.

Signed-off-by: Takashi Iwai <tiwai@suse.de>