Merge pull request ARMmbed#1801 from ARMmbed/rf_driver_start_fix

Add MAC TX active FLAG to active before write function return value.

Author: Juha Heiskanen

source/MAC/IEEE802_15_4/mac_pd_sap.c

@@ -137,21 +137,21 @@ int8_t mac_plme_cca_req(protocol_interface_rf_mac_setup_s *rf_mac_setup) {
     dev_driver_tx_buffer_s *tx_buf = &rf_mac_setup->dev_driver_tx_buffer;
     phy_device_driver_s *dev_driver = rf_mac_setup->dev_driver->phy_driver;
 
-
+    rf_mac_setup->macRfRadioTxActive = true;
     if (dev_driver->arm_net_virtual_tx_cb) {
         if (dev_driver->tx(tx_buf->buf, tx_buf->len, 1, PHY_LAYER_PAYLOAD) == 0) {
-            rf_mac_setup->macRfRadioTxActive = true;
             timer_mac_start(rf_mac_setup, MAC_TX_TIMEOUT, NWKTX_TIMEOUT_PERIOD);  /*Start Timeout timer for virtual packet loss*/
         } else {
+            rf_mac_setup->macRfRadioTxActive = false;
             mac_data_interface_tx_to_cb(rf_mac_setup);
         }
         return 0;
     }
 
     if (dev_driver->tx(tx_buf->buf, tx_buf->len, 1, PHY_LAYER_PAYLOAD) == 0) {
-        rf_mac_setup->macRfRadioTxActive = true;
         return 0;
     }
+    rf_mac_setup->macRfRadioTxActive = false;
     return -1;
 }