arm64: dts: qcom: ipq8074: drop the clock-frequency property

Drop the clock-frequency property from the MMIO timer node, since it
is already configured by the bootloader.

Signed-off-by: Kathiravan T <quic_kathirav@quicinc.com>
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Link: https://lore.kernel.org/r/1643819709-5410-2-git-send-email-quic_kathirav@quicinc.com