Convert the Qualcomm RPMH RSC bindings to DT Schema.

Changes against original bindings:
1. Add qcom,tcs-offset as a property instead of one of reg (not used
   that way).
2. Add limits to interrupts.
3. Add child nodes (bcm-voter, clock-controller, power-controller).
4. Extend the example with more complex one.

The device description and DTS examples were copied from existing
sources, so keep the license as GPL-2.0-only.
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Link: https://lore.kernel.org/r/20220411085935.130072-4-krzysztof.kozlowski@linaro.org