AR5K_SET_SHORT_PREAMBLE
.hw_value_short = ATH5K_RATE_CODE_2M | AR5K_SET_SHORT_PREAMBLE,
.hw_value_short = ATH5K_RATE_CODE_5_5M | AR5K_SET_SHORT_PREAMBLE,
.hw_value_short = ATH5K_RATE_CODE_11M | AR5K_SET_SHORT_PREAMBLE,
reg + (AR5K_SET_SHORT_PREAMBLE << 2));