arm64: dts: qcom: sm8250: Fix level triggered PMU interrupt polarity

As per interrupt documentation for SM8250 SoC, the polarity
for level triggered PMU interrupt is low, fix this.

Fixes: 60378f1a ("arm64: dts: qcom: sm8250: Add sm8250 dts file")
Signed-off-by: Sai Prakash Ranjan <saiprakash.ranjan@codeaurora.org>
Link: https://lore.kernel.org/r/96680a1c6488955c9eef7973c28026462b2a4ec0.1613468366.git.saiprakash.ranjan@codeaurora.org


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