usb: uac2: Add ACHeader and FormatType descriptor

Add missing, but needed, ACHeader and FormatType descriptor definitions.
Signed-off-by: Yadi Brar <yadi.brar01@gmail.com>
Signed-off-by: Jassi Brar <jaswinder.singh@linaro.org>
Signed-off-by: Felipe Balbi <balbi@ti.com>

include/linux/usb/audio-v2.h

@@ -43,6 +43,27 @@ static inline bool uac2_control_is_writeable(u32 bmControls, u8 control)
 	return (bmControls >> (control * 2)) & 0x2;
 }
 
+/* 4.7.2 Class-Specific AC Interface Descriptor */
+struct uac2_ac_header_descriptor {
+	__u8  bLength;			/* 9 */
+	__u8  bDescriptorType;		/* USB_DT_CS_INTERFACE */
+	__u8  bDescriptorSubtype;	/* UAC_MS_HEADER */
+	__le16 bcdADC;			/* 0x0200 */
+	__u8  bCategory;
+	__le16 wTotalLength;		/* includes Unit and Terminal desc. */
+	__u8  bmControls;
+} __packed;
+
+/* 2.3.1.6 Type I Format Type Descriptor (Frmts20 final.pdf)*/
+struct uac2_format_type_i_descriptor {
+	__u8  bLength;			/* in bytes: 6 */
+	__u8  bDescriptorType;		/* USB_DT_CS_INTERFACE */
+	__u8  bDescriptorSubtype;	/* FORMAT_TYPE */
+	__u8  bFormatType;		/* FORMAT_TYPE_1 */
+	__u8  bSubslotSize;		/* {1,2,3,4} */
+	__u8  bBitResolution;
+} __packed;
+
 /* 4.7.2.1 Clock Source Descriptor */
 
 struct uac_clock_source_descriptor {