lte_disconnect(): wait less

instead of first delaying 300ms and then testing whether the modem is ready (AT), do the test first and delay afterwards if needed

in normal situations this will save 300ms, otherwise it won't make a difference

Author: peter-pycom

esp32/mods/modlte.c

@@ -1189,10 +1189,10 @@ STATIC mp_obj_t lte_disconnect(mp_obj_t self_in) {
         lteppp_set_state(E_LTE_ATTACHED);
         lte_push_at_command("ATH", LTE_RX_TIMEOUT_MAX_MS);
         while (true) {
-            mp_hal_delay_ms(LTE_RX_TIMEOUT_MIN_MS);
             if (lte_push_at_command("AT", LTE_RX_TIMEOUT_MAX_MS)) {
                 break;
             }
+            mp_hal_delay_ms(LTE_RX_TIMEOUT_MIN_MS);
         }
         lte_check_attached(lte_legacyattach_flag);
         mod_network_deregister_nic(&lte_obj);