dt-bindings: timer: renesas,tpu: remove binding documentation

commit 1c4b5ec ("remove the h8300 architecture") removes Renesas TPU
timer driver. Let's remove its binding documentation.

Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://lore.kernel.org/r/87semglt2g.wl-kuninori.morimoto.gx@renesas.com
Signed-off-by: Uwe Kleine-König <ukleinek@kernel.org>

Author: morimoto

Documentation/devicetree/bindings/pwm/renesas,tpu-pwm.yaml

@@ -9,15 +9,6 @@ title: Renesas R-Car Timer Pulse Unit PWM Controller
 maintainers:
   - Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
 
-select:
-  properties:
-    compatible:
-      contains:
-        const: renesas,tpu
-  required:
-    - compatible
-    - '#pwm-cells'
-
 properties:
   compatible:
     items: