The ornamental design for a bushing, as shown and described.
FIG. 1 is a perspective view of a bushing showing my new design;
FIG. 2 is a front elevational view thereof;
FIG. 3 is a rear elevational view thereof;
FIG. 4 is a side elevational view of one side thereof, the opposite side elevational view being a mirror image thereof, the top and bottom plan views being identical to FIG. 4; and,
FIG. 5 is a cross-section taken along line 5-5 of FIG. 2.