Fixed FHSS get retry period (ARMmbed#2543)

Author: Jarkko Paso

source/Service_Libs/fhss/fhss_ws.c

@@ -929,7 +929,7 @@ static uint32_t fhss_ws_get_retry_period_callback(const fhss_api_t *api, uint8_t
     uint32_t cur_time_us = fhss_structure->callbacks.read_timestamp(fhss_structure->fhss_api);
     uint32_t tx_trig_offset_us = (txrx_slot_length_us / 2) * calc_own_tx_trig_slot(fhss_structure->own_hop);
 
-    uint32_t next_tx_trig_slot_start_us = unicast_start_us + (txrx_slot_length_us * !fhss_ws_check_tx_allowed(fhss_structure)) + tx_trig_offset_us;
+    uint32_t next_tx_trig_slot_start_us = unicast_start_us + (txrx_slot_length_us * (fhss_structure->own_hop & 1)) + tx_trig_offset_us;
     uint32_t next_tx_trig_slot_end_us = next_tx_trig_slot_start_us + (txrx_slot_length_us / 2);
     while ((next_tx_trig_slot_start_us < cur_time_us) || ((next_tx_trig_slot_start_us - cur_time_us) > (uint32_t) MS_TO_US(fhss_structure->ws->fhss_configuration.fhss_broadcast_interval))) {
         if (cur_time_us < next_tx_trig_slot_end_us) {