ALSA: usb-audio: Set correct type for some UAC2 mixer controls.

Changed ctl type for Input Gain Control and Input Gain Pad Control to
USB_MIXER_S16 as per section 5.2.5.7.11-12 in the USB Audio Class 2.0
definition.
Signed-off-by: Johan Rastén <johan@oljud.se>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

sound/usb/mixer.c

@@ -809,12 +809,12 @@ static struct usb_feature_control_info audio_feature_info[] = {
 	{ "Tone Control - Treble",	USB_MIXER_S8 },
 	{ "Graphic Equalizer",		USB_MIXER_S8 }, /* FIXME: not implemeted yet */
 	{ "Auto Gain Control",		USB_MIXER_BOOLEAN },
-	{ "Delay Control",		USB_MIXER_U16 },
+	{ "Delay Control",		USB_MIXER_U16 }, /* FIXME: U32 in UAC2 */
 	{ "Bass Boost",			USB_MIXER_BOOLEAN },
 	{ "Loudness",			USB_MIXER_BOOLEAN },
 	/* UAC2 specific */
-	{ "Input Gain Control",		USB_MIXER_U16 },
-	{ "Input Gain Pad Control",	USB_MIXER_BOOLEAN },
+	{ "Input Gain Control",		USB_MIXER_S16 },
+	{ "Input Gain Pad Control",	USB_MIXER_S16 },
 	{ "Phase Inverter Control",	USB_MIXER_BOOLEAN },
 };