ARM: dts: qcom: msm8974: add xo clock to rpm clock controller

Populate the rpm clock controller node with clocks and clock-names
properties.

Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Reviewed-by: Konrad Dybcio <konrad.dybcio@linaro.org>
Signed-off-by: Bjorn Andersson <andersson@kernel.org>
Link: https://lore.kernel.org/r/20221227001547.2830656-1-dmitry.baryshkov@linaro.org