dt-bindings: clock: renesas,cpg-mssr: Document r8a779a0

Add binding documentation for the R-Car V3U (R8A779A0) Clock Pulse
Generator.

Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Link: https://lore.kernel.org/r/1599470390-29719-7-git-send-email-yoshihiro.shimoda.uh@renesas.com
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>

Documentation/devicetree/bindings/clock/renesas,cpg-mssr.yaml

@@ -47,6 +47,7 @@ properties:
       - renesas,r8a77980-cpg-mssr # R-Car V3H
       - renesas,r8a77990-cpg-mssr # R-Car E3
       - renesas,r8a77995-cpg-mssr # R-Car D3
+      - renesas,r8a779a0-cpg-mssr # R-Car V3U
 
   reg:
     maxItems: 1