I'm not sure the amount of sleep is directly correlated with intelligence, and if it is I'd be also skeptical one directly influenced the other evolutionarily speaking.
To begin with, you have a very small pool of "very intelligent" animals, out of which humans outcompete all of them remarkably. So your sample size is an issue. Your second issue is how exactly you define and measure intelligence.
The amount of sleep is most likely an adaptation to various factors such as diet, amount of energy spent and needed, environmental pressures, etc.
Koalas sleep most hours of the day and trust me, they are not exactly smart or carnivorous. They sleep to preserve energy digesting, and they are not alone in this- snakes also nap after meals. As for cats and dogs, cats in particular are adapted to preserve energy. It's almost like their life motto. In the wild this allows them to go by without food for long stretches of time, very useful when you rely on prey availability.