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>
diff --git a/fdts/stm32mp157c-dhcom-pdk2.dts b/fdts/stm32mp157c-dhcom-pdk2.dts
new file mode 100644
index 0000000..370a69a
--- /dev/null
+++ b/fdts/stm32mp157c-dhcom-pdk2.dts
@@ -0,0 +1,26 @@
+// SPDX-License-Identifier: GPL-2.0-or-later OR BSD-3-Clause
+/*
+ * Copyright (C) 2019-2020 Marek Vasut <marex@denx.de>
+ * Copyright (C) 2022 DH electronics GmbH
+ *
+ * DHCOM STM32MP1 variant:
+ * DHCM-STM32MP157C-C065-R102-F0819-SPI-E2-CAN2-SDR104-RTC-WBT-T-DSI-I-01D2
+ * DHCOM PCB number: 587-200 or newer
+ * PDK2 PCB number: 516-400 or newer
+ */
+/dts-v1/;
+
+#include "stm32mp157.dtsi"
+#include "stm32mp15xc.dtsi"
+#include "stm32mp15xx-dhcom-som.dtsi"
+#include "stm32mp15xx-dhcom-pdk2.dtsi"
+
+/ {
+	model = "DH electronics STM32MP157C DHCOM Premium Developer Kit (2)";
+	compatible = "dh,stm32mp157c-dhcom-pdk2", "dh,stm32mp157c-dhcom-som",
+		     "st,stm32mp157";
+};
+
+&cryp1 {
+	status = "okay";
+};