ARM: dts: stm32: Add SPL specifics for DH STM32MP13xx DHCOR DHSBC

ARM: dts: stm32: Add SPL specifics for DH STM32MP13xx DHCOR DHSBC

Add SPL specific DT additions to DH STM32MP13xx DHCOR DHSBC . These
include I2C3 configuration which is required to access the PMIC,
PMIC regulator and QSPI NOR bootph-all properties to allow SPL to
configure PMIC buck regulators and load from QSPI NOR respectively,
etzpc bus switch to simple-bus to prevent interference from TFABOOT
specific configuration, and RCC configuration to define clock tree
configuration used by this platform.

Reviewed-by: Patrice Chotard <patrice.chotard@foss.st.com>
Signed-off-by: Marek Vasut <marek.vasut@mailbox.org>