arm64: dts: qcom: sm8350: drop duplicated ref_clk in UFS

ref_clk clock in UFS node is already there with a <0 0> frequency, which
matches other DTSI files.

Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Link: https://lore.kernel.org/r/20220407092725.232463-3-krzysztof.kozlowski@linaro.org