Fix i2c_algo_dp_aux_exec() such that it handles all transactions needed by our i2c framework.  Unbreaks EDID fetching over displayport.
Fix i2c_algo_dp_aux_exec() such that it handles all transactions needed by
our i2c framework.  Unbreaks EDID fetching over displayport.

ok jsg@

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