dt-bindings: soc: qcom: smd-rpm: extend example

Replace existing limited example with proper code for Qualcomm Resource
Power Manager (RPM) over SMD based on MSM8916.  This also fixes the
example's indentation.

Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Link: https://lore.kernel.org/r/20220723082358.39544-2-krzysztof.kozlowski@linaro.org