The ornamental design for the panel for air conditioner, as shown and described.
FIG. 1 is a perspective view of the front, right and top sides of a panel for air conditioner showing my new design;
FIG. 2 is a front view thereof;
FIG. 3 is a rear view thereof;
FIG. 4 is a left side view thereof;
FIG. 5 is a right side view thereof;
FIG. 6 is a top view thereof;
FIG. 7 is perspective view shown in a position of use thereof; and,
FIG. 8 is another perspective view shown in a position of use thereof.
The broken line showing of the panel for air conditioner is included for the purpose of illustrating portions of the panel for air conditioner and forms no part of the claimed design.