I claim, the ornamental design for a LED lamp, as shown and described.
FIG. 1 is a perspective view of an LED lamp showing my new design;
FIG. 2 is a front elevation view thereof, with the rear elevation view being a mirror image of the front;
FIG. 3 is a left side elevation view thereof, with the right elevation view being a mirror image of the left;
FIG. 4 is a top plan view thereof; and,
FIG. 5 is a bottom plan view thereof.
The elements for which the design is claimed are shown in solid lines, the broken lines are shown for illustrative purposes only and form no part of the claimed design.