dt-bindings: usb: atmel,at91rm9200-udc: convert to DT schema

dt-bindings: usb: atmel,at91rm9200-udc: convert to DT schema

Convert Atmel AT91 USB Device Controller (UDC) binding to DT schema.
Changes during conversion:
- Include "atmel,pullup-gpio" and "atmel,matrix" in the properties since
  they are required by existing in-tree DTS definitions.

Reviewed-by: Rob Herring (Arm) <robh@kernel.org>
Signed-off-by: Charan Pedumuru <charan.pedumuru@gmail.com>
Link: https://patch.msgid.link/20260327-atmel-usb-v4-4-eb8b6e49b29d@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>