ARM: dts: stm32: Add STM32MP257F Evaluation board support

Add STM32MP257F Evaluation board support. It embeds a STM32MP257FAI SoC,
with 4GB of DDR4, TSN switch (2+1 ports), 2*USB typeA, 1*USB2 typeC,
SNOR OctoSPI, mini PCIe, STPMIC2 for power distribution ...

Sync device tree with kernel v6.6-rc1.

Signed-off-by: Patrice Chotard <patrice.chotard@foss.st.com>
Reviewed-by: Patrick Delaunay <patrick.delaunay@foss.st.com>
diff --git a/arch/arm/dts/stm32mp25xc.dtsi b/arch/arm/dts/stm32mp25xc.dtsi
new file mode 100644
index 0000000..5e83a69
--- /dev/null
+++ b/arch/arm/dts/stm32mp25xc.dtsi
@@ -0,0 +1,8 @@
+// SPDX-License-Identifier: (GPL-2.0-or-later OR BSD-3-Clause)
+/*
+ * Copyright (C) STMicroelectronics 2023 - All Rights Reserved
+ * Author: Alexandre Torgue <alexandre.torgue@foss.st.com> for STMicroelectronics.
+ */
+
+/ {
+};