video: of: fix memory leak

If of_parse_display_timing() fails we are printing an error message and
jumping to the error path but we missed freeing "dt".

Signed-off-by: Sudip Mukherjee <[e-mail]>
Signed-off-by: Tomi Valkeinen <[e-mail]>

drivers/video/of_display_timing.c

···
 			 */
 			pr_err("%s: error in timing %d\n",
 				of_node_full_name(np), disp->num_timings + 1);
+			kfree(dt);
 			goto timingfail;
 		}