ARM: dts: stm32mp13: alignment with v5.19

Device tree alignment with Linux kernel v5.19-rc1 with:
- ARM: dts: stm32: add UserPA13 button on stm32mp135f-dk
- ARM: dts: stm32: add blue led (Linux heartbeat) on stm32mp135f-dk
- ARM: dts: stm32: add EXTI interrupt-parent to pinctrl node on stm32mp131
- ARM: dts: stm32: enable RTC support on stm32mp135f-dk
- ARM: dts: stm32: add RTC node on stm32mp131
- ARM: dts: stm32: fix pinctrl node name warnings (MPU soc)

Signed-off-by: Patrick Delaunay <patrick.delaunay@foss.st.com>
Reviewed-by: Patrice Chotard <patrice.chotard@foss.st.com>