usb: gadget: Use correct APIs and data types for UUID handling

We have two types for UUIDs depending on the byte ordering.
Instead of explaining how bytes should go over the wire,
use dedicated APIs and data types. This removes a confusion
over the byte ordering.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Tested-By: Jó Ágila Bitsch <jgilab@gmail.com>
Link: https://lore.kernel.org/r/20230125143425.85268-1-andriy.shevchenko@linux.intel.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/gadget/composite.c

@@ -829,7 +829,7 @@ static int bos_desc(struct usb_composite_dev *cdev)
 	if (cdev->use_webusb) {
 		struct usb_plat_dev_cap_descriptor *webusb_cap;
 		struct usb_webusb_cap_data *webusb_cap_data;
-		uuid_t webusb_uuid = WEBUSB_UUID;
+		guid_t webusb_uuid = WEBUSB_UUID;
 
 		webusb_cap = cdev->req->buf + le16_to_cpu(bos->wTotalLength);
 		webusb_cap_data = (struct usb_webusb_cap_data *) webusb_cap->CapabilityData;
@@ -841,7 +841,7 @@ static int bos_desc(struct usb_composite_dev *cdev)
 		webusb_cap->bDescriptorType = USB_DT_DEVICE_CAPABILITY;
 		webusb_cap->bDevCapabilityType = USB_PLAT_DEV_CAP_TYPE;
 		webusb_cap->bReserved = 0;
-		export_uuid(webusb_cap->UUID, &webusb_uuid);
+		export_guid(webusb_cap->UUID, &webusb_uuid);
 
 		if (cdev->bcd_webusb_version != 0)
 			webusb_cap_data->bcdVersion = cpu_to_le16(cdev->bcd_webusb_version);

include/linux/usb/webusb.h

@@ -11,15 +11,12 @@
 #include "uapi/linux/usb/ch9.h"
 
 /*
- * little endian PlatformCapablityUUID for WebUSB
+ * Little Endian PlatformCapablityUUID for WebUSB
  * 3408b638-09a9-47a0-8bfd-a0768815b665
- * to identify Platform Device Capability descriptors as referring to WebUSB
- *
- * the UUID above MUST be sent over the wire as the byte sequence:
- * {0x38, 0xB6, 0x08, 0x34, 0xA9, 0x09, 0xA0, 0x47, 0x8B, 0xFD, 0xA0, 0x76, 0x88, 0x15, 0xB6, 0x65}.
+ * to identify Platform Device Capability descriptors as referring to WebUSB.
  */
 #define WEBUSB_UUID \
-	UUID_INIT(0x38b60834, 0xa909, 0xa047, 0x8b, 0xfd, 0xa0, 0x76, 0x88, 0x15, 0xb6, 0x65)
+	GUID_INIT(0x3408b638, 0x09a9, 0x47a0, 0x8b, 0xfd, 0xa0, 0x76, 0x88, 0x15, 0xb6, 0x65)
 
 /*
  * WebUSB Platform Capability data