The ornamental design for a mobiledevice, as shown and described.
FIG. 1 is a front perspective view of a mobile device showing our new design;
FIG. 2 is a front view thereof;
FIG. 3 is a rear view thereof;
FIG. 4 is a right side view thereof;
FIG. 5 is a left side view thereof;
FIG. 6 is a top view thereof; and,
FIG. 7 is a bottom view thereof.
The broken line showing of portions of the mobile device is for the purpose of illustrating environmental structure and forms no part of the claimed design. In the drawings, the stippled shading represents surfaces having the contrast in appearance shown.