R92C_RF_AC
rf_ac[i] = rtwn_rf_read(sc, i, R92C_RF_AC);
rtwn_rf_write(sc, i, R92C_RF_AC,
rtwn_rf_write(sc, i, R92C_RF_AC, rf_ac[i]);
rf_ac[i] = urtwn_rf_read(sc, i, R92C_RF_AC);
urtwn_rf_write(sc, i, R92C_RF_AC,
urtwn_rf_write(sc, i, R92C_RF_AC, rf_ac[i]);