dt-bindings: soc: qcom,smsm: convert to dtschema

Convert the Qualcomm Shared Memory State Machine to DT schema.

Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Link: https://lore.kernel.org/r/20220405065512.26521-1-krzysztof.kozlowski@linaro.org