dt-bindings: phy: renesas,usb2-phy: Document RZ/G3S phy bindings

Document the RZ/G3S PHY bindings. The RZ/G3S USB PHY is almost identical
with the RZ/G2L USB PHY. The difference is that there is a hardware
limitation on the max burst size used when the BUS master interface
issues a transfer request for RZ/G3S that is configured though PHY
registers.

Signed-off-by: Claudiu Beznea <claudiu.beznea.uj@bp.renesas.com>
Acked-by: Conor Dooley <conor.dooley@microchip.com>
Link: https://lore.kernel.org/r/20240822152801.602318-12-claudiu.beznea.uj@bp.renesas.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>

Author: claudiubeznea

Documentation/devicetree/bindings/phy/renesas,usb2-phy.yaml

@@ -13,7 +13,9 @@ properties:
   compatible:
     oneOf:
       - items:
-          - const: renesas,usb2-phy-r8a77470 # RZ/G1C
+          - enum:
+              - renesas,usb2-phy-r8a77470  # RZ/G1C
+              - renesas,usb2-phy-r9a08g045 # RZ/G3S
 
       - items:
           - enum: