The ornamental design for a displaydevice, as shown and described.
FIG. 1 is a perspective view of a display device in accordance with our new design;
FIG. 2 is a front view thereof;
FIG. 3 is a rear view thereof;
FIG. 4 is a left view thereof;
FIG. 5 is a right view thereof;
FIG. 6 is a top plan view thereof; and,
FIG. 7 is a bottom plan view thereof.
The broken lines immediately adjacent the claimed areas represent the bounds of the claimed design while all other broken lines are directed to environment and are for illustrative purposes only. The broken lines form no part of the claimed design.