dt-bindings: phy: document Allwinner A523 USB-2.0 PHY

The Allwinner A523 SoC contains a USB-2.0 PHY fully compatible to the
one used in the D1/T113s SoCs. This PHY controls the two USB-2.0 ports,
there is a separate and quite different PHY for the USB-3.0 port.

Add the new compatible string, with a fallback to the D1 version.

Signed-off-by: Andre Przywara <andre.przywara@arm.com>
Acked-by: Conor Dooley <conor.dooley@microchip.com>
Link: https://lore.kernel.org/r/20250307005712.16828-8-andre.przywara@arm.com


Signed-off-by: Vinod Koul <vkoul@kernel.org>