arm64: dts: qcom: sm8450-nagara: Add GPIO keys

With PMIC GPIOs now available, set up required pin settings and add
gpio-keys.

Signed-off-by: Konrad Dybcio <konrad.dybcio@linaro.org>
Signed-off-by: Bjorn Andersson <andersson@kernel.org>
Link: https://lore.kernel.org/r/20221229103212.984324-4-konrad.dybcio@linaro.org