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