dt-bindings: usb: npcm7xx: Add npcm845 compatible

Add a compatible string for Nuvoton BMC NPCM845 USB EHCI host controller.

Acked-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: Tomer Maimon <tmaimon77@gmail.com>
Link: https://lore.kernel.org/r/20220718181842.61040-3-tmaimon77@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>