manifest: update openthread repo to include a fix for OpenThread

Remove a legacy Mbed TLS error code that was removed in TF-PSA-Crypto
used by the OpenThread module.

Signed-off-by: Valerio Setti <vsetti@baylibre.com>

Author: valeriosetti

west.yml

@@ -385,7 +385,7 @@ manifest:
       revision: 5efe7974f9546582e99f5a842a816ea4b65f5227
       path: modules/lib/open-amp
     - name: openthread
-      revision: 9a40380a47b2493cfcd172b362704581e9aef47f
+      revision: pull/225/head
       path: modules/lib/openthread
     - name: percepio
       path: modules/debug/percepio