The ornamental design for a frontportion of an automobile, as shown and described.
FIG. 1 is a front perspective view of a front portion of an automobile of our new design;
FIG. 2 is a rear perspective view thereof;
FIG. 3 is a right side view thereof, the left side view being a mirror image thereof;
FIG. 4 is a front view thereof;
FIG. 5 is a rear view thereof; and,
FIG. 6 is a top plan view thereof.
The bottom view of the front portion of the automobile forms no part of the claimed design. The lighter contrast portion of the automobile in the photographs is shown to illustrate environment and forms no part of the claimed design.