base-sim: increase operator identifier loading timeout

SIMCOM A760xE-H modems can answer to AT+CRSM=176,28589,0,0,4 request in 10s or more, so use rather big timeout (20s)

src/mm-base-sim.c

@@ -2147,11 +2147,13 @@ load_operator_identifier (MMBaseSim *self,
 {
     mm_obj_dbg (self, "loading operator ID...");
 
-    /* READ BINARY of EFad (Administrative Data) ETSI 51.011 section 10.3.18 */
+    /* READ BINARY of EFad (Administrative Data) ETSI 51.011 section 10.3.18
+     * SIMCOM A760xE-H modems can answer in 10s or more, so use rather big timeout
+     */
     mm_base_modem_at_command (
         self->priv->modem,
         "+CRSM=176,28589,0,0,4",
-        10,
+        20,
         FALSE,
         (GAsyncReadyCallback)load_operator_identifier_command_ready,
         g_task_new (self, NULL, callback, user_data));