arm64: dts: qcom: msm8992: Add PMU node

Add the PMU so we can get proper perf event support on this SoC.

Signed-off-by: Konrad Dybcio <konradybcio@gmail.com>
Link: https://lore.kernel.org/r/20200625182118.131476-10-konradybcio@gmail.com


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