feat(stm32mp15-fdts): add support for STM32MP157C based DHCOM SoM on PDK2 board

This is an SoM in SODIMM-200 format on an evaluation board called
"DHCOM Premium Developer Kit #2" (DHCOM PDK2 for short). The SoM features an
STM32MP157C SoC with 1 GB DDR3, 8 GB eMMC, microSD and 2 MB SPI flash.
The baseboard has multiple UART, USB, SPI, and I2C ports/headers and several
other interfaces that are not important for TF-A.

These dts(i) files are based on DHCOM dt's from Linux 5.16 and U-Boot 2022.01.
The DRAM calibration values are taken from U-Boot 2022.01 and are optimized for
industrial temperature range above 85° C.

TF-A on this board was fully tested with the latest OP-TEE developer setup.

Change-Id: I696c01742954d761fbad312cd1059e3ab01fa93c
Signed-off-by: Johann Neuhauser <jneuhauser@dh-electronics.com>
5 files changed