[ALSA] usb-audio - SB Live24-External better handling

This patch improves support for 'SB Live 24-bit Extarnal' USB card.
1) This card can go into muted state when a headphones connected or
disconnected. So notify mixer about changes in headphone jack.
2) Add LED controls and procfs support just as in similar Audigy 2 NX card.
3) Rename 'PCM Capture' conrol to 'Mic Capture' to reflect reality:
the card may adjust microphone input level only.

Signed-off-by: Timofei Bondarenko <tim@ipi.ac.ru>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Jaroslav Kysela <perex@perex.cz>

sound/usb/usbmixer_maps.c

@@ -187,6 +187,13 @@ static struct usbmix_selector_map audigy2nx_selectors[] = {
 	{ 0 } /* terminator */
 };
 
+/* Creative SoundBlaster Live! 24-bit External */
+static struct usbmix_name_map live24ext_map[] = {
+	/* 2: PCM Playback Volume */
+	{ 5, "Mic Capture" }, /* FU, default PCM Capture Volume */
+	{ 0 } /* terminator */
+};
+
 /* LineX FM Transmitter entry - needed to bypass controls bug */
 static struct usbmix_name_map linex_map[] = {
 	/* 1: IT pcm */
@@ -273,6 +280,10 @@ static struct usbmix_ctl_map usbmix_ctl_maps[] = {
 		.map = audigy2nx_map,
 		.selector_map = audigy2nx_selectors,
 	},
+ 	{
+		.id = USB_ID(0x041e, 0x3040),
+		.map = live24ext_map,
+	},
 	{
 		/* Hercules DJ Console (Windows Edition) */
 		.id = USB_ID(0x06f8, 0xb000),