Remove unused RX boosted gain mode functions and related preprocessor directives across multiple variants

variants/rak11310/target.cpp

@@ -36,13 +36,4 @@ void radio_set_tx_power(int8_t dbm) {
 mesh::LocalIdentity radio_new_identity() {
   RadioNoiseListener rng(radio);
   return mesh::LocalIdentity(&rng);  // create new random identity
-}
-#if defined(USE_SX1262) || defined(USE_SX1268)
-void radio_set_rx_boosted_gain_mode(bool rxbgm) {
-  radio.setRxBoostedGainMode(rxbgm);
-}
-
-bool radio_get_rx_boosted_gain_mode() {
-  return radio.getRxBoostedGainMode();
-}
-#endif
+}