ARM: dts: qcom: pm8226: Add thermal sensor and thermal zone config

Add thermal sensor, which is using on chip VADC channel to report PMIC
die temperature. Also add the corresponding thermal zone.

Signed-off-by: Matti Lehtimäki <matti.lehtimaki@gmail.com>
Signed-off-by: Bjorn Andersson <andersson@kernel.org>
Link: https://lore.kernel.org/r/20230529221501.43455-2-matti.lehtimaki@gmail.com