[openthread] Enable `OPENTHREAD_CONFIG_PLATFORM_UDP_ENABLE`.

Change-Id: I708cd98c16dd11e4017d673e1b8a0b193988b6c8

Reviewed-on: https://fuchsia-review.googlesource.com/c/third_party/openthread/+/642686
Reviewed-by: Jiaming Wang <jiamingw@google.com>
diff --git a/include/openthread-config-fuchsia.h b/include/openthread-config-fuchsia.h
index 5be6ac5..1fdd15c 100644
--- a/include/openthread-config-fuchsia.h
+++ b/include/openthread-config-fuchsia.h
@@ -45,6 +45,9 @@
 /* Define to 1 if you want to enable Border Routing */
 #define OPENTHREAD_CONFIG_BORDER_ROUTING_ENABLE 0
 
+/* Define to 1 if you want to enable platform UDP. */
+#define OPENTHREAD_CONFIG_PLATFORM_UDP_ENABLE 1
+
 /* Define to 1 if you want to enable backbone router support */
 #define OPENTHREAD_CONFIG_BACKBONE_ROUTER_ENABLE 0