Correctly set lowest_present_ofdm in iwm_mvm_ack_rates().
Correctly set lowest_present_ofdm in iwm_mvm_ack_rates().

ok phessler@, stsp@

orumin/openbsd-efivars,orumin/openbsd-efivars,orumin/openbsd-efivars,orumin/openbsd-efivars