[ALSA] ac97: YMF743 missing controls support (2/2)

These patches enable a few YMF743 controls (Tone/3D/IEC958) that won't
be detected with the current version of ALSA.
The second one contains following changes:
- A chip-specific SPDIF support for YMF743 (It doesn't have AC97
 standard SPDIF registers seen on YMF753).
- The implementation for 'IEC958 Playback Source' and 'IEC958 Mute'
 are identical to the ones for YMF753. But there is no 'IEC958 Output
 Pin' for YMF743.

Signed-off-by: Keita Maehara <maehara@debian.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Jaroslav Kysela <perex@suse.cz>

sound/pci/ac97/ac97_id.h

@@ -54,6 +54,7 @@
 #define AC97_ID_ALC658		0x414c4780
 #define AC97_ID_ALC658D		0x414c4781
 #define AC97_ID_ALC850		0x414c4790
+#define AC97_ID_YMF743		0x594d4800
 #define AC97_ID_YMF753		0x594d4803
 #define AC97_ID_VT1616		0x49434551
 #define AC97_ID_CM9738		0x434d4941