ARM: dts: stm32: Add support for STM32MP13xx DHCOR SoM and DHSBC board

ARM: dts: stm32: Add support for STM32MP13xx DHCOR SoM and DHSBC board

This stm32mp135f-dhcor-dhsbc board is a stack of DHCOR SoM based on
STM32MP135F SoC (900MHz / crypto capabilities) populated on DHSBC
carrier board.

The SoM contains the following peripherals:
- STPMIC (power delivery)
- 512MB DDR3L memory
- eMMC and SDIO WiFi module

The DHSBC carrier board contains the following peripherals:
- Two RGMII Ethernet ports
- USB-A Host port, USB-C peripheral port, USB-C power supply plug
- Expansion connector

Reviewed-by: Patrice Chotard <patrice.chotard@foss.st.com>
Signed-off-by: Marek Vasut <marex@denx.de>