si-adapter: use a different g_autoptr for port_format

modules/module-si-adapter.c

@@ -306,7 +306,7 @@ si_adapter_activate_execute_step (WpSessionItem * item,
       break;
 
     case STEP_CONFIGURE_PORTS: {
-      g_autoptr (WpSpaPod) format = NULL;
+      g_autoptr (WpSpaPod) format = NULL, port_format = NULL;
       g_autoptr (WpSpaPod) pod = NULL;
 
       /* set the chosen device/client format on the node */
@@ -317,13 +317,13 @@ si_adapter_activate_execute_step (WpSessionItem * item,
       self->format.format = SPA_AUDIO_FORMAT_F32P;
       self->format.rate = 48000;
 
-      format = format_audio_raw_build (&self->format);
+      port_format = format_audio_raw_build (&self->format);
       pod = wp_spa_pod_new_object ("PortConfig",  "PortConfig",
           "direction",  "I", self->direction,
           "mode",       "I", SPA_PARAM_PORT_CONFIG_MODE_dsp,
           "monitor",    "b", self->monitor,
           "control",    "b", self->control_port,
-          "format",     "P", format,
+          "format",     "P", port_format,
           NULL);
       wp_proxy_set_param (WP_PROXY (self->node), SPA_PARAM_PortConfig, 0, pod);