dt-bindings: clock: renesas,cpg-mssr: Document r8a774e1

Add binding documentation for the RZ/G2H (R8A774E1) Clock Pulse Generator
driver.

Signed-off-by: Marian-Cristian Rotariu <marian-cristian.rotariu.rb@bp.renesas.com>
Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Link: https://lore.kernel.org/r/1594138692-16816-9-git-send-email-prabhakar.mahadev-lad.rj@bp.renesas.com
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>

Author: marian-c-rotariu

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

@@ -33,6 +33,7 @@ properties:
       - renesas,r8a774a1-cpg-mssr # RZ/G2M
       - renesas,r8a774b1-cpg-mssr # RZ/G2N
       - renesas,r8a774c0-cpg-mssr # RZ/G2E
+      - renesas,r8a774e1-cpg-mssr # RZ/G2H
       - renesas,r8a7790-cpg-mssr  # R-Car H2
       - renesas,r8a7791-cpg-mssr  # R-Car M2-W
       - renesas,r8a7792-cpg-mssr  # R-Car V2H