dt-bindings: usb: ti,keystone-dwc3: drop assigned-clocks

The meta schema from DT schema already defines assigned-clocks, so there
is no need for device schema to mention it at all.  There are also no
benefits of having it here.

Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Acked-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20230403191850.374839-3-krzysztof.kozlowski@linaro.org


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>