stm32mp1: Add device tree files

Those device tree files are taken from STM32MP1 U-Boot and Linux.
And they are updated to fit TF-A needs.

Signed-off-by: Yann Gautier <yann.gautier@st.com>
Signed-off-by: Lionel Debieve <lionel.debieve@st.com>
diff --git a/fdts/stm32mp157c-ev1.dts b/fdts/stm32mp157c-ev1.dts
new file mode 100644
index 0000000..98a9d35
--- /dev/null
+++ b/fdts/stm32mp157c-ev1.dts
@@ -0,0 +1,25 @@
+// SPDX-License-Identifier: (GPL-2.0+ OR BSD-3-Clause)
+/*
+ * Copyright (C) STMicroelectronics 2017 - All Rights Reserved
+ * Author: Ludovic Barre <ludovic.barre@st.com> for STMicroelectronics.
+ */
+
+/dts-v1/;
+#include "stm32mp157c-ed1.dts"
+
+/ {
+	model = "STMicroelectronics STM32MP157C-EV1 pmic eval daughter on eval mother";
+	compatible = "st,stm32mp157c-ev1", "st,stm32mp157c-ed1", "st,stm32mp157";
+
+	chosen {
+		bootargs = "earlyprintk console=ttyS3,115200 root=/dev/ram";
+		stdout-path = "serial3:115200n8";
+	};
+};
+
+&usart3 {
+	pinctrl-names = "default";
+	pinctrl-0 = <&usart3_pins_a>;
+	resets = <&rcc USART3_R>;
+	status = "disabled";
+};