cdc-phonet: use common parser

This moves cdc-phonet to the common parser for CDC users
to reduce code duplication.

Signed-off-by: Oliver Neukum <oneukum@suse.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/usb/cdc-phonet.c

@@ -340,32 +340,13 @@ static int usbpn_probe(struct usb_interface *intf, const struct usb_device_id *i
 	u8 *data;
 	int phonet = 0;
 	int len, err;
+	struct usb_cdc_parsed_header hdr;
 
 	data = intf->altsetting->extra;
 	len = intf->altsetting->extralen;
-	while (len >= 3) {
-		u8 dlen = data[0];
-		if (dlen < 3)
-			return -EINVAL;
-
-		/* bDescriptorType */
-		if (data[1] == USB_DT_CS_INTERFACE) {
-			/* bDescriptorSubType */
-			switch (data[2]) {
-			case USB_CDC_UNION_TYPE:
-				if (union_header || dlen < 5)
-					break;
-				union_header =
-					(struct usb_cdc_union_desc *)data;
-				break;
-			case 0xAB:
-				phonet = 1;
-				break;
-			}
-		}
-		data += dlen;
-		len -= dlen;
-	}
+	cdc_parse_cdc_header(&hdr, intf, data, len);
+	union_header = hdr.usb_cdc_union_desc;
+	phonet = hdr.phonet_magic_present;
 
 	if (!union_header || !phonet)
 		return -EINVAL;