The ornamental design for a spatula, as shown and described.
FIG. 1 is an isometric view of a front, top, and a first side of an ornamental design for a spatula;
FIG. 2 is a top elevational view of the spatula of FIG. 1;
FIG. 3 is an elevational view of the first side of the spatula of FIG. 1, wherein a second, opposite side of the spatula is a mirror image of the first side; and,
FIG. 4 is a front elevational view of the spatula of FIG. 1.
The broken lines in the drawings depict environmental subject matter only and form no part of the claimed design.