Fix data race in radio::is_start_of_burst.

lib/include/srsran/radio/radio.h

@@ -104,7 +104,7 @@ private:
   bool decimator_busy = false; ///< Indicates the decimator is changing the rate
 
   rf_timestamp_t    end_of_burst_time = {};
-  bool           is_start_of_burst  = false;
+  std::atomic<bool> is_start_of_burst{false};
   uint32_t          tx_adv_nsamples    = 0;
   double            tx_adv_sec         = 0.0; // Transmission time advance to compensate for antenna->timestamp delay
   bool              tx_adv_auto        = false;