[ALSA] hda-intel - Show more volume-knob attributes

Show more attributs of volume-knob widgets.
Also don't put empty lines when no connection list is found.

Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Jaroslav Kysela <perex@perex.cz>

sound/pci/hda/hda_codec.h

@@ -135,6 +135,7 @@ enum {
 #define AC_PAR_PROC_CAP			0x10
 #define AC_PAR_GPIO_CAP			0x11
 #define AC_PAR_AMP_OUT_CAP		0x12
+#define AC_PAR_VOL_KNB_CAP		0x13
 
 /*
  * AC_VERB_PARAMETERS results (32bit)