ALSA: hda - Fix silent HP output on D975

Some desktops seems to have no HP/mic jack detection on the front panel,
which results in the silent output in the recent driver, because the
driver mutes the output (to save power) when no plug is detected.

This patch adds a new model that disables the jack-detection.

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

Documentation/sound/alsa/ALSA-Configuration.txt

@@ -1063,6 +1063,7 @@ Prior to version 0.9.0rc4 options had a 'snd_' prefix. This was removed.
 
 	STAC9227/9228/9229/927x
 	  ref		Reference board
+	  ref-no-jd	Reference board without HP/Mic jack detection
 	  3stack	D965 3stack
 	  5stack	D965 5stack + SPDIF
 	  dell-3stack	Dell Dimension E520