US D571039 S1
The ornamental design for a lighting device, as shown and described.
FIG. 1 is a perspective view of the lighting device in accordance with our new design;
FIG. 2 is a bottom view thereof; and,
FIG. 3 is a front side view thereof, the right side, left side and rear side views being identical to the front side view.
The portions shown in broken lines are for illustrative purposes only and form no part of the claimed design.