feat(stm32mp15-fdts): add Avenger96 board with STM32MP157A DHCOR SoM

This should replace the stm32mp157a-avenger96.dts with the new device
tree files split into the STM32MP15 DHCOR SoM definition and the
Avenger96 baseboard like it's done in Linux and U-Boot.

Differences to stm32mp157a-avenger96.dts:
- Enable sdmmc2 for booting from eMMC
- improved clock settings like in U-Boot commit b6055945
  "ARM: dts: stm32: Adjust PLL4 settings on AV96 again"
- improved DDR settings for DHSOMs like in U-Boot commit 92ca0f74
  "ARM: dts: stm32: Synchronize DDR setttings on DH SoMs"

TF-A with this new dts(i) files on this board was fully tested with
the latest OP-TEE developer setup.

Change-Id: I85ce8eca7747965af3555fc19fd7b192dc3e5740
Signed-off-by: Johann Neuhauser <jneuhauser@dh-electronics.com>
diff --git a/fdts/stm32mp157a-dhcor-avenger96.dts b/fdts/stm32mp157a-dhcor-avenger96.dts
new file mode 100644
index 0000000..82d48aa
--- /dev/null
+++ b/fdts/stm32mp157a-dhcor-avenger96.dts
@@ -0,0 +1,24 @@
+// SPDX-License-Identifier: GPL-2.0 OR BSD-3-Clause
+/*
+ * Copyright (C) Linaro Ltd 2019 - All Rights Reserved
+ * Author: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
+ * Copyright (C) 2020 Marek Vasut <marex@denx.de>
+ * Copyright (C) 2022 DH electronics GmbH
+ *
+ * DHCOR STM32MP1 variant:
+ * DHCR-STM32MP157A-C065-R102-V18-SPI-C-01LG
+ * DHCOR PCB number: 586-100 or newer
+ * Avenger96 PCB number: 588-200 or newer
+ */
+
+/dts-v1/;
+
+#include "stm32mp157.dtsi"
+#include "stm32mp15xx-dhcor-som.dtsi"
+#include "stm32mp15xx-dhcor-avenger96.dtsi"
+
+/ {
+	model = "Arrow Electronics STM32MP157A Avenger96 board";
+	compatible = "arrow,stm32mp157a-avenger96", "dh,stm32mp157a-dhcor-som",
+		     "st,stm32mp157";
+};