ALSA: usb-audio: Add bi-directional terminal types

Define the bi-directional USB terminal types for audio devices.
Signed-off-by: Jorge Sanjuan <jorge.sanjuan@codethink.co.uk>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

include/uapi/linux/usb/audio.h

@@ -230,6 +230,14 @@ struct uac1_output_terminal_descriptor {
 #define UAC_OUTPUT_TERMINAL_COMMUNICATION_SPEAKER	0x306
 #define UAC_OUTPUT_TERMINAL_LOW_FREQ_EFFECTS_SPEAKER	0x307
 
+/* Terminals - 2.4 Bi-directional Terminal Types */
+#define UAC_BIDIR_TERMINAL_UNDEFINED			0x400
+#define UAC_BIDIR_TERMINAL_HANDSET			0x401
+#define UAC_BIDIR_TERMINAL_HEADSET			0x402
+#define UAC_BIDIR_TERMINAL_SPEAKER_PHONE		0x403
+#define UAC_BIDIR_TERMINAL_ECHO_SUPPRESSING		0x404
+#define UAC_BIDIR_TERMINAL_ECHO_CANCELING		0x405
+
 /* Set bControlSize = 2 as default setting */
 #define UAC_DT_FEATURE_UNIT_SIZE(ch)		(7 + ((ch) + 1) * 2)