The ornamental design of the display panel, as shown and described.
FIG. 1 is a perspective view of a display panel; the broken line showing connection structure is for illustration purposes only and forms no part of the claimed design;
FIG. 2 is a front elevation view of the display panel of FIG. 1;
FIG. 3 is a top plan view of the display panel of FIG. 1; the broken line showing connection structure is for illustration purposes only and forms no part of the claimed design;
FIG. 4 is a side elevation view of the display panel of FIG. 1; the broken line showing connection structure is for illustration purposes only and forms no part of the claimed design;
FIG. 5 is a back elevation view of the display panel of FIG. 1; the broken line showing connection structure is for illustration purposes only and forms no part of the claimed design; and,
FIG. 6 is a bottom plan view of the display panel of FIG. 1; the broken line showing connection structure is for illustration purposes only and forms no part of the claimed design.