Set Net example to use IAD device class

examples/device/net_lwip_webserver/src/usb_descriptors.c

@@ -56,9 +56,11 @@ tusb_desc_device_t const desc_device =
     .bDescriptorType    = TUSB_DESC_DEVICE,
     .bcdUSB             = 0x0200,
 
-    .bDeviceClass       = TUSB_CLASS_UNSPECIFIED,
-    .bDeviceSubClass    = 0,
-    .bDeviceProtocol    = 0,
+    // Use Interface Association Descriptor (IAD) device class
+    .bDeviceClass       = TUSB_CLASS_MISC,
+    .bDeviceSubClass    = MISC_SUBCLASS_COMMON,
+    .bDeviceProtocol    = MISC_PROTOCOL_IAD,
+    
     .bMaxPacketSize0    = CFG_TUD_ENDPOINT0_SIZE,
 
     .idVendor           = 0xCafe,