remove LORA_CR fallback from target.cpp on xiao_nrf52, xiao_s3 and t-echo

variants/techo/target.cpp

@@ -18,10 +18,6 @@ TechoSensorManager sensors = TechoSensorManager(nmea);
   DISPLAY_CLASS display;
 #endif
 
-#ifndef LORA_CR
-  #define LORA_CR      5
-#endif
-
 bool radio_init() {
   rtc_clock.begin(Wire);