You can just put it in the keg, no need to do anything with the yeast. After two weeks, a regular strength beer will have fermented out, so there's little CO2 going to be produced.
Even if there were some CO2 produced, it takes time for the forced carbonation to enter solution, so any additional co2 from the yeast just contributes to the pressure in the headspace which is then topped up to your target psi by the co2 tank. Any co2 from the yeast simply means you use a fraction less co2 from the tank, but it's a small amount and not worth worrying about.
Stopping the yeast would not be good for the beer, since it's needed to condition and improve the beer. After two weeks, the beer is still pretty green - another couple of weeks with the small amount of yeast in suspension cleans up the beer.