The ornamental design for a light mount, as shown and described.
FIG. 1 is a perspective view of a light mount showing our new design;
FIG. 2 is a side view of the same;
FIG. 3 is an end view of the same;
FIG. 4 is a top view of the same; and,
FIG. 5 is another top view of the same, wherein the boat and the water are shown in broken lines for environmental purposes only and form no part of the claimed design.
For the purposes of this application, the sides of the light mount are mirror images of one another and the ends of the light mount are mirror images of one another.