The ornamental design for a trackingdevice, as shown and described.
FIG. 1 is a top, front, and right side perspective view of a tracking device;
FIG. 2 is a bottom and rear side perspective view thereof;
FIG. 3 is a front elevational view thereof;
FIG. 4 is a rear elevational view thereof;
FIG. 5 is a left side elevational view thereof;
FIG. 6 is a right side elevational view thereof;
FIG. 7 is a top plan view thereof; and,
FIG. 8 is a bottom plan view thereof.
The broken lines in the drawings showing portions of the tracking device are included for the purpose of illustrating environmental structure and form no part of the claimed design.