Introduce new st,stm32mp25-rtc compatible. It is based on st,stm32mp1-rtc.

Difference is that stm32mp25 soc implements a triple protection on RTC
registers:
- Secure bit based protection
- Privileged context based protection
- Compartment ID filtering based protection
This driver will now check theses configurations before probing to avoid
exceptions and fake reads on register.

Link: https://www.st.com/resource/en/reference_manual/rm0457-stm32mp25xx-advanced-armbased-3264bit-mpus-stmicroelectronics.pdf#page=4081Signed-off-by: Valentin Caron <valentin.caron@foss.st.com>
Reviewed-by: Rob Herring (Arm) <robh@kernel.org>
Link: https://lore.kernel.org/r/20240708153434.416287-2-valentin.caron@foss.st.comSigned-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>