The ornamental design for a cover for mobilephone, as shown and described.
FIG. 1 is a front perspective view of a cover for mobile phone showing our new design;
FIG. 2 is a front view thereof;
FIG. 3 is a rear view thereof;
FIG. 4 is a left-side view thereof;
FIG. 5 is a right-side view thereof;
FIG. 6 is a top view thereof; and,
FIG. 7 is a bottom view thereof.
The broken lines immediately adjacent shaded surfaces represent the bounds of the claimed design. All other broken lines depict unclaimed environment. The broken lines form no part of the claimed design.