schema CHANGE support extension instance top-level in ly_path_compile()

For further support of serching schema nodes in extension instance
instead of the standard module tree, we need to extend internal
ly_path_compile().
diff --git a/src/xpath.c b/src/xpath.c
index d05107f..6846ef7 100644
--- a/src/xpath.c
+++ b/src/xpath.c
@@ -3714,7 +3714,7 @@
             oper = (sleaf->flags & LYS_IS_OUTPUT) ? LY_PATH_OPER_OUTPUT : LY_PATH_OPER_INPUT;
 
             /* it was already evaluated on schema, it must succeed */
-            rc = ly_path_compile(set->ctx, lref->cur_mod, &sleaf->node, lref->path, LY_PATH_LREF_TRUE, oper,
+            rc = ly_path_compile(set->ctx, lref->cur_mod, &sleaf->node, NULL, lref->path, LY_PATH_LREF_TRUE, oper,
                     LY_PATH_TARGET_MANY, LY_PREF_SCHEMA_RESOLVED, lref->prefixes, NULL, &p);
             assert(!rc);