dt-bindings: thermal: qcom-spmi-temp-alarm: Improve thermal zone in example

The current example for a thermal zone isn't very useful as reference
since it would result in a hardware shutdown at 145°C, instead of
allowing the system to try to shutdown gracefully. Without an ADC
channel a maximum of two trip points is useful in practice for this
sensor, with temperatures corresponding to the stage 1 and stage 2
'hardware trip points'. A critical trip point at stage 2 may allow the
system to shutdown before a hardware shutdown at stage 3 kicks in. It
should be noted though that by default the chip performs a 'partial
shutdown' when the temperature reaches stage 2, which may prevent an
orderly shutdown. The 'partial shutdown' can be disabled by software.

Signed-off-by: Matthias Kaehlcke <mka@chromium.org>
Reviewed-by: Douglas Anderson <dianders@chromium.org>
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Eduardo Valentin <edubezval@gmail.com>