dt-bindings: usb: samsung,exynos-dwc3: convert to dtschema

Convert the Samsung Exynos SoC USB 3.0 DWC3 Controller bindings to DT
schema format.

Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>
Link: https://lore.kernel.org/r/20220302190938.6195-2-krzysztof.kozlowski@canonical.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>