dt-bindings: pwm: renesas,tpu-pwm: Document r8a7742 support

Document r8a7742 specific compatible strings. No driver change is
needed as the fallback compatible string "renesas,tpu" activates the
right code in the driver.
Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Reviewed-by: Marian-Cristian Rotariu <marian-cristian.rotariu.rb@bp.renesas.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Acked-by: Rob Herring <robh@kernel.org>
Acked-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>

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

@@ -15,6 +15,7 @@ properties:
       - enum:
           - renesas,tpu-r8a73a4   # R-Mobile APE6
           - renesas,tpu-r8a7740   # R-Mobile A1
+          - renesas,tpu-r8a7742   # RZ/G1H
           - renesas,tpu-r8a7743   # RZ/G1M
           - renesas,tpu-r8a7744   # RZ/G1N
           - renesas,tpu-r8a7745   # RZ/G1E