The ornamental design for a device mount, as shown and described.
FIG. 1 is a front perspective view of a device mount;
FIG. 2 is a front elevational view thereof;
FIG. 3 is a rear elevational view thereof;
FIG. 4 is a left-side elevational view thereof;
FIG. 5 is a right-side elevational view thereof;
FIG. 6 is a top plan view thereof; and,
FIG. 7 is a bottom plan view thereof.
The shade lines in the figures show contour and not surface ornamentation.
The dashed broken lines depict portions of the device mount that form no part of the claimed design. The dot-dashed broken lines represent boundaries of the claimed device mount and form no part of the claimed design.