Remove LTE link establish routines

The code used was already deprecated and the library should not be
responsible over what network it communicates, just that it
communicates over a network and handle it as a transparant layer.

README.md

@@ -54,7 +54,13 @@ int main() {
 ```
 
 ### Connecting
-The module takes care of modem enabling, socket creating and connecting to the server automatically. You just have to configure URL and port of the Thingsboard CoAP server, using `config COAP_CLIENT_NUM_MSGS` and `config COAP_CLIENT_MSG_LEN`. CoAP reliability can be fine-tuned using `config COAP_NUM_RETRIES` and the Zephyr-internal `config COAP_INIT_ACK_TIMEOUT_MS`. Using NB-IoT, 15000 is a good starting value for the latter.
+
+The module takes care of socket creating and connecting to the server automatically. You just have
+to configure URL and port of the Thingsboard CoAP server, using `config COAP_CLIENT_NUM_MSGS` and
+`config COAP_CLIENT_MSG_LEN`.
+
+CoAP reliability can be fine-tuned using `config COAP_NUM_RETRIES` and the Zephyr-internal
+`config COAP_INIT_ACK_TIMEOUT_MS`. Using NB-IoT, 15000 is a good starting value for the latter.
 
 ### Sending telemetry to cloud
 ```c

src/thingsboard.c

@@ -194,24 +194,6 @@ static void time_worker(struct k_work *work) {
 	k_work_schedule(&work_time, K_MSEC(TIME_RETRY_INTERVAL));
 }
 
-static void modem_configure(void)
-{
-#if defined(CONFIG_LTE_LINK_CONTROL)
-	if (IS_ENABLED(CONFIG_LTE_AUTO_INIT_AND_CONNECT)) {
-		/* Do nothing, modem is already turned on
-		 * and connected.
-		 */
-	} else {
-		int err;
-
-		LOG_INF("LTE Link Connecting ...");
-		err = lte_lc_init_and_connect();
-		__ASSERT(err == 0, "LTE link could not be established.");
-		LOG_INF("LTE Link Connected!");
-	}
-#endif /* defined(CONFIG_LTE_LINK_CONTROL) */
-}
-
 int thingsboard_send_telemetry(const void *payload, size_t sz) {
 	int err;
 
@@ -225,38 +207,6 @@ int thingsboard_send_telemetry(const void *payload, size_t sz) {
 	return 0;
 }
 
-static void print_modem_info(void) {
-	char info_name[50];
-	char modem_info[50];
-
-	enum modem_info infos[] = {
-		MODEM_INFO_FW_VERSION,
-		MODEM_INFO_UICC,
-		MODEM_INFO_IMSI,
-		MODEM_INFO_ICCID,
-		MODEM_INFO_APN,
-		MODEM_INFO_IP_ADDRESS
-	};
-
-	int ret;
-
-	for (size_t i = 0; i < ARRAY_SIZE(infos); i++) {
-		ret = modem_info_string_get(infos[i],
-						modem_info,
-						sizeof(modem_info));
-		if (ret < 0) {
-			return;
-		}
-		ret = modem_info_name_get(infos[i],
-						info_name);
-		if (ret < 0 || ret > sizeof(info_name)) {
-			return;
-		}
-		info_name[ret] = '\0';
-		LOG_INF("Value of %s is %s", info_name, modem_info);
-	}
-}
-
 static void start_client(void);
 
 static const struct tb_fw_id *current_fw;
@@ -319,10 +269,6 @@ int thingsboard_init(attr_write_callback_t cb, const struct tb_fw_id *fw_id) {
 
 	current_fw = fw_id;
 
-	modem_configure();
-
-	print_modem_info();
-
 	if (coap_client_init(start_client) != 0) {
 		LOG_ERR("Failed to initialize CoAP client");
 		return -1;