COMBINE garlic salt, rosemary, thyme and black pepper in small bowl. Sprinkle pork with half of spice mixture.
HEAT oil in large, nonstick skillet over medium heat. Add pork and cook on each side for 3 minutes or until browned and cooked through. Remove from skillet; set aside and keep warm.
REDUCE heat to low. Add flour, evaporated milk and remaining spice mixture to skillet. Stir to loosen brown bits from bottom of skillet. Cook for 3 minutes. Add grapes and cook for an additional minute until thickened.
PLACE pork on serving platter and top with sauce.