dt-bindings: timer: renesas,tmu: add r8a779a0 TMU support

Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Reviewed-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://lore.kernel.org/r/20210607124828.1984-1-wsa+renesas@sang-engineering.comSigned-off-by: Rob Herring <robh@kernel.org>

Documentation/devicetree/bindings/timer/renesas,tmu.yaml

@@ -36,6 +36,7 @@ properties:
           - renesas,tmu-r8a77980 # R-Car V3H
           - renesas,tmu-r8a77990 # R-Car E3
           - renesas,tmu-r8a77995 # R-Car D3
+          - renesas,tmu-r8a779a0 # R-Car V3U
       - const: renesas,tmu
 
   reg: