dt: thermal: tsens: Document the fallback DT property for v2 of TSENS IP

We want to create common code for v2 of the TSENS IP block that is used in
a large number of Qualcomm SoCs. "qcom,tsens-v2" should be able to handle
most of the common functionality start with a common get_temp() function.

It is also necessary to split out the memory regions for the TM and SROT
register banks because their offsets are not constant across SoC families.

Signed-off-by: Amit Kucheria <amit.kucheria@linaro.org>
Reviewed-by: Rob Herring <robh@kernel.org>
Reviewed-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Tested-by: Matthias Kaehlcke <mka@chromium.org>
Reviewed-by: Matthias Kaehlcke <mka@chromium.org>
Reviewed-by: Douglas Anderson <dianders@chromium.org>
Signed-off-by: Eduardo Valentin <edubezval@gmail.com>