fix(wifi): prevent crash in WPS-registrar due to nested 'eap_wsc_reset()' calls

When a WPS handshake is already in progress and the enrollee sends another EAPOL-Start
(e.g., due to missed packets or timeout), the registrar resets its state by calling
'eap_wsc_reset()'. This function frees 'sm->eap_method_priv' and then calls
'esp_wifi_ap_wps_disable()', which internally triggers another call to 'eap_wsc_reset()'.

This results in a double reset where the second invocation accesses the already freed
'sm->eap_method_priv', leading to a crash.

This fix sets 'sm->eap_method_priv' to NULL immediately after freeing it to ensure
any subsequent calls to eap_wsc_reset() do not access an invalid pointer.

Author: sarveshb14

components/wpa_supplicant/src/eap_server/eap_server_wsc.c

@@ -104,6 +104,7 @@ static void eap_wsc_reset(struct eap_sm *sm, void *priv)
 	//wps_deinit(data->wps);
 	os_free(data);
 #ifdef ESP_SUPPLICANT
+	sm->eap_method_priv = NULL;
 	/* TODO: When wps-registrar is shifted in a separate task other than wifi task,
 	 * call esp_wifi_ap_wps_disable() here instead of wifi_ap_wps_disable_internal()
 	 * */