If the condensation is in between the liner and the shell, just take the liners out of the boot at the end of the day...
If the wetness is on the inside of the liner, the wetness is actually probably sweat (unless your somehow getting snow inside your boot), which you really can't avoid, it happens a lot when your skiing on warmer days. It can be annoying (and quite smelly), but the best way to get it out of there is to use a boot dryer at the end of the day.