parser xml BUGFIX missing value hint for XML opaq attrs

Fixes sysrepo/sysrepo#2708
diff --git a/src/parser_xml.c b/src/parser_xml.c
index 7db2b9a..276ccc1 100644
--- a/src/parser_xml.c
+++ b/src/parser_xml.c
@@ -210,7 +210,8 @@
 
         /* attr2 is always changed to the created attribute */
         ret = lyd_create_attr(NULL, &attr2, xmlctx->ctx, name, name_len, prefix, prefix_len, ns ? ns->uri : NULL,
-                ns ? strlen(ns->uri) : 0, xmlctx->value, xmlctx->value_len, &xmlctx->dynamic, format, val_prefix_data, 0);
+                ns ? strlen(ns->uri) : 0, xmlctx->value, xmlctx->value_len, &xmlctx->dynamic, format, val_prefix_data,
+                LYD_HINT_DATA);
         LY_CHECK_GOTO(ret, cleanup);
 
         if (!*attr) {