dt-bindings: phy: renesas: Document Renesas RZ/G3E USB3.0 PHY

dt-bindings: phy: renesas: Document Renesas RZ/G3E USB3.0 PHY

Document Renesas RZ/G3E USB3.0 PHY. This IP is connected between
USB3HOST and PHY module. The main functions of the module are
as follows:
 - Reset control
 - Control of PHY input pins
 - Monitoring of PHY output pins

Acked-by: Conor Dooley <conor.dooley@microchip.com>
Signed-off-by: Biju Das <biju.das.jz@bp.renesas.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://patch.msgid.link/20251029084037.108610-2-biju.das.jz@bp.renesas.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>