R92C_SIFS_CCK
rtwn_write_1(sc, R92C_SIFS_CCK + 1, 10);
rtwn_write_2(sc, R92C_SIFS_CCK, 0x1010);
urtwn_write_1(sc, R92C_SIFS_CCK + 1, sifs_time);
urtwn_write_2(sc, R92C_SIFS_CCK, 0x100a);