[ALSA] ac97 - Enable S/PDIF on ASUS P5P800-VM mobo

The attached patch will force building the S/PDIF controls on the PCU
SSID for Asus P5P800-VM motherboard, even if the  AC97_EI_SPDIF bit is
not set.

Signed-off-by: Magnus Sandin <magnus@sandin.cx>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Jaroslav Kysela <perex@suse.cz>