The ornamental design for the roofing panel, as shown and described.
FIG. 1 is a front view of the roofing panel showing my new design;
FIG. 2 is a top plain view thereof;
FIG. 3 is a rear view thereof;
FIG. 4 is a bottom view thereof;
FIG. 5 is a right side view thereof; and,
FIG. 6 is a left side view thereof.
The cut-out portion presented as parallel zig-zag lines define any lengths of the panel not present in order to indicate the overall length of the panel may be of any measurement and has no limit; thus, such cut-out portions within the claimed design form no part thereof.