If the bar and the lot are open to the general public, and you have a business license and a liquor license, the police are going to stay if they want to.
If you don't want them parking in the lot, they can always park on the street, walk in, and stand by the front door. Would you prefer that?
Perhaps if you explain what the real issue is with the officers in the lot? Is it that they are catching people staggering out of the club after having been served too much? Underage? Following people and making DUI arrests?
If they are causing a "hassle" it might be because there is a perceived problem with the place, or the patrons attending the business. In my town we have a number of bars, but only one where there are nightly issues. The owner there complains that we are hassling them. Well, no, we're watching the place and making more walk throughs because there are more problems in that particular bar and just outside of it. We don't give the other places nearly as much attention because they are not involved in the same level of trouble.
Unless GA is out of step with much of the rest of the country, you don't have much of a leg to stand on here. And I doubt it is a fight that a nightclub owner wants to have.