Preheat oven to 350°F. Place turkey skin side down between 2 layers of plastic wrap and pound with a meat mallet or the bottom of a heavy skillet to flatten breast as thinly as possible. Sprinkle on both sides with jerk seasoning and garlic salt, then place skin side down on a cutting board. Stir together all mango stuffing ingredients in a medium bowl. Pile mixture down the center of turkey breast. Starting on the longer side, roll up tightly to enclose stuffing. Tie in 3 or 4 places with kitchen string and place seam side down on a large baking sheet. Bake for 1 1/2 hours or until turkey is cooked through, tenting with foil if surface browns too quickly. Let stand 10 minutes before slicing.