The ornamental design for fitting for furniture, as shown and described.
1. Fitting for furniture
1.1: Perspective
1.2: Front
1.3: Back
1.4: Left
1.5: Right
1.6: Top
1.7: Bottom
The broken lines shown in the drawings are for the purpose of illustrating portions of the fitting for furniture that form no part of the claimed design. The design shows a piece for an actuating-arm of furniture flaps.