Add a digi_dietemp node for the STM32 Digital Temperature Sensor into
stm32h723.dtsi (used as a base for H723, H725, H730 and H735) and
stm32h7a3.dtsi (used as a base for H7A3, H7B0 and H7B3).
The sensor is not available on other H7 SoCs.
Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>