The ornamental design for a display mount, as shown and described.
FIG. 1 is a perspective view of a display mount showing my new design;
FIG. 2 is a front view thereof;
FIG. 3 is a rear view thereof;
FIG. 4 is a left side view thereof;
FIG. 5 is a right side view thereof;
FIG. 6 is a top plan view thereof; and,
FIG. 7 is a bottom plan view thereof.
The dashed or broken lines shown in the drawings depict portions of the display mount in which the design is embodied that form no part of the claimed design.