dt-bindings: qcom-qce: document optional clocks and clock-names properties

On newer Qualcomm SoCs the crypto engine clocks are enabled by default
by security firmware. To drop clocks and clock-names from the list of
required properties use 'qcom,sm8150-qce' compatible name.

The change is based on Neil Armstrong's observation and an original change.

Cc: Neil Armstrong <neil.armstrong@linaro.org>
Signed-off-by: Vladimir Zapolskiy <vladimir.zapolskiy@linaro.org>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>