[ALSA] hda_intel: add ATI RS690 HDMI audio support

This patch adds support for the HDMI codec of the ATI RS690 IGP northbridge.

Signed-off-by: Felix Kuehling <fkuehlin@ati.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Jaroslav Kysela <perex@suse.cz>