The ornamental design for a frontportion of a vehicle, as shown and described.
FIG. 1 is an elevational view of a front portion of a vehicle showing my new design;
FIG. 2 is a side elevational view of one side thereof, the opposite side elevational view being a mirror image; and,
FIG. 3 is a perspective view thereof.
The broken line showing of the rectangular area on the front grille and the headlights are for illustrative purposes only and form no part of the claimed design. The jagged line indicates a boundary of the claim and is not part of the claimed design.