arm64: dts: qcom: pmr735a: stop depending on thermal_zones label

Most of SoC device trees do not provide the thermal_zones label. Thus
stop depending on it and use the full path to the thermal zones nodes.

Fixes: 7a3544e5 ("arm64: dts: qcom: pmr735a: Add temp-alarm support")
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>