media: uvcvideo: Document how to format GUIDs

media: uvcvideo: Document how to format GUIDs

Manual formatting the GUIDs can lead to errors, document a
programmatically way to format the GUIDs from lsusb into something that
the driver can use.

Signed-off-by: Ricardo Ribalda <ribalda@chromium.org>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Hans de Goede <johannes.goede@oss.qualcomm.com>
Signed-off-by: Hans de Goede <johannes.goede@oss.qualcomm.com>
Signed-off-by: Hans Verkuil <hverkuil+cisco@kernel.org>