arm64: dts: qcom: pmk8550: add reboot-mode node using sdam_2 nvmem

arm64: dts: qcom: pmk8550: add reboot-mode node using sdam_2 nvmem

Introduce sdam_2 node, which is to be used via nvmem for power on
reasons during reboot. Add supported PoN reasons supported via sdam_2
node.

Signed-off-by: Neil Armstrong <neil.armstrong@linaro.org>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Tested-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: Bjorn Andersson <andersson@kernel.org>
Link: https://lore.kernel.org/r/20230503-topic-sm8450-upstream-reboot-reason-v1-2-c5ac3dd5b49f@linaro.org