arm64: dts: qcom: ipq8074: add clock-frequency to MDIO node

Add clock-frequency to MDIO node to set the MDC rate to 6.25Mhz instead
of using the default value of 390KHz from MDIO default divider.

Signed-off-by: Christian Marangi <ansuelsmth@gmail.com>
Reviewed-by: Konrad Dybcio <konrad.dybcio@linaro.org>
Link: https://lore.kernel.org/r/20240131022731.2118-1-ansuelsmth@gmail.com


Signed-off-by: Bjorn Andersson <andersson@kernel.org>