Well its not the GFI if the pool was wired proplerly if it's kicked all the lights in the pool will be off.
If the pool light in question can be turned on seperatly from the other lights in the pool it may be the low voltage relay that the equipment uses to turn on/off the high voltage. These relays are a moving part and offten fail. They "can" be taken apart and the connectors cleaned but generally once a relay starts sparking on its cycle it will fail again, and should be replaced.
If the pool light is only controled with the other lights on/off and it has intermitant on/off its something singular to that light, either the light it's self, blub with a weak element etc. Most likely couperate is the junction box that splits off the lights from the power comming from the control box. This is generally a round black box with a square head (looks like a hat) these damp area junction boxs have to be mounted above the water line, and may be in a planter or other soil area around the pool. Find it, and make sure those connections in the box are proper.
Hope this helps.