m_config_frontend: use m_option_set_node_or_string

There is a usage of m_option_parse which exactly mirrors the intention
of the helper function m_option_set_node_or_string. Instead of
duplicating the logic, just call the m_option_set_node_or_string
instead.

options/m_config_frontend.c

@@ -788,13 +788,7 @@ int m_config_set_option_node(struct m_config *config, bstr name,
     // the old value, as opposed to e.g. appending to lists.
     union m_option_value val = m_option_value_default;
 
-    if (data->format == MPV_FORMAT_STRING) {
-        bstr param = bstr0(data->u.string);
-        r = m_option_parse(mp_null_log, co->opt, name, param, &val);
-    } else {
-        r = m_option_set_node(co->opt, &val, data);
-    }
-
+    r = m_option_set_node_or_string(mp_null_log, co->opt, name, &val, data);
     if (r >= 0)
         r = m_config_set_option_raw(config, co, &val, flags);