xiao_c6: fallback for LORA_CR is set in std_init

variants/xiao_c6/target.cpp

@@ -16,10 +16,6 @@ ESP32RTCClock fallback_clock;
 AutoDiscoverRTCClock rtc_clock(fallback_clock);
 SensorManager sensors;
 
-#ifndef LORA_CR
-  #define LORA_CR      5
-#endif
-
 bool radio_init() {
   fallback_clock.begin();
   rtc_clock.begin(Wire);