ALSA: usb-audio: add UAC2 sepecific Feature Unit controls

The bits to enable them are always 0 for UAC1 devices, so no additional
checks are required.
Signed-off-by: Daniel Mack <daniel@caiaq.de>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

sound/usb/mixer.c

@@ -696,6 +696,10 @@ static struct usb_feature_control_info audio_feature_info[] = {
 	{ "Delay Control",		USB_MIXER_U16 },
 	{ "Bass Boost",			USB_MIXER_BOOLEAN },
 	{ "Loudness",			USB_MIXER_BOOLEAN },
+	/* UAC2 specific */
+	{ "Input Gain Control",		USB_MIXER_U16 },
+	{ "Input Gain Pad Control",	USB_MIXER_BOOLEAN },
+	{ "Phase Inverter Control",	USB_MIXER_BOOLEAN },
 };