We claim the ornamental design for a mounting interface, as shown and described.
FIG. 1 is a perspective view of a mounting interface; and,
FIG. 2 is a top plan view of the mounting interface.
The ornamental design which is claimed is shown in solid lines in the drawings. The broken lines in the drawings are for illustrative purposes only and form no part of the claimed design. No claim is made to the thickness of the mounting interface, shown in broken lines. The thickness and other dimensions are shown in broken lines and form no part of the claimed design.